The journal, which is accessed by default by pressing the F1 key, provides some pretty important information. In spite of this, it is explained well neither in the manual nor in any of the other documentation I've found to date. Thus, I will try to explain each important aspect of each page of the journal. First, it bears mentioning that the different pages of the journal may be accessed by pressing the right and left arrow keys and that the journal may be closed at any time by pressing the escape key.
The specials page, shown below, displays the various special weapons throughout the game with which the current character can perform weapon-specific combos. As stated elsewhere, any character can wield any weapon, but outside of his area of specialty, the character's use of the weapon will be clumsy at best. The following illustration shows the special weapons with which Sargon is proficient. Note well: the specials page will not be available until the character has progressed a certain "distance" into the game.

The information displayed for each weapon is in essentially the same format as that used on the weapons page of the journal. For an explanation of what the various numbers and symbols mean, refer to that section in this document. The only additional information displayed on this page consists of the various pictures that demonstrate what special kind of damage is done by the weapon. For example, the drop of blood indicates that the Queen's Sword has a vampiric or life-stealing attack, the snowflake indicates that the Ice Sword does cold damage—which is tremendously effective, for example, against fire golems—the fire indicates that the Fire Sword does fire damage (surprise, surprise) and the sun indicates that the Sword of Ianna does light/magic damage as a tool of the "forces of light". In my own experience with Sargon, the Ice Sword is the best of the bunch when it comes to melee damage from its combo, whereas the Sword of Ianna is indispensable at the end of the game for reasons that will become clear as you play—be sure to collect all six runes! Click here to view Zoe's specials page instead.
The weapons page of the journal, pictured below, displays information about all of the weapons with which the current character can perform weapon-specific combos. The information displayed for each weapon includes its attack power, defense modifier, the name of the associated weapon-specific combo, the control combination to execute it and the requisite character level to perform it. Note well: any character may use any weapon in the game, but he will be able to use the most devastating combos only for those weapons that are shown on the weapons page of his journal. Honestly, it isn't worth the effort to use weapons with which the character is not comfortable, no matter how cool they may look. If you absolutely must use that monster implement of destruction you just found, then play another character!

The above image is the weapons page of Sargon's journal. Click here to view Zoe's weapons page or Nagflar's weapons page. Note carefully that all of the weapons with weapon-specific combos at his disposal are one-handed swords and maces, which is his area of specialization. Even though Sargon may use one-handed swords that do not appear on this page, he may not activate any weapon-specific combos with them. At most, he may use his own character-specific abilities, as discussed in the section covering the abilities page of the journal. For example, Sargon may put an Orc Sword to good use, but he will never be able to deal the kind of damage with it that, say, the Elf Sword will do.
Speaking of the Elf Sword, that weapon will provide a good basis for discussing the information displayed on this page. Notice that the Elf Sword appears in the fourth row of the leftmost column of the table. To the far left of its entry, a miniature picture or icon of the sword is displayed. Above it, in small yellow lettering, appears "+50A", which means that the Elf Sword has a +50 to the overall attack rating of the character when equipped. As discussed elsewhere, this does not guarantee a particular amount of damage, but it means that on average the Elf Sword will do more damage with a normal attack than, say, a Gladius, and do less than, say, a Heavy Sword. Harder still to read is the "-25D" in small red lettering beneath the icon of the sword, which (not surprisingly) means that the Elf Sword has as -25 to the overall defense rating of the character when equipped. Speaking generally, the more devastating a weapon is in terms of its damage, the more it opens the character to enemy attack. Those who have studied fencing, kendo or other such arts will likely find this quite realistic as I do.
Moving to the right, beneath where the name of the Elf Sword is given, one finds the name of the special weapon-specific combo for this weapon, namely, The Dream. Below the name of the weapon-specific combo, however, is a potentially confusing bunch of icons with what might be a somewhat more intuitive "L.9" to the right. The "L.9" means simply that Sargon cannot use The Dream attack until he is at least experience level nine. Once he reaches experience level nine, his player may activate The Dream by pressing the key combination(s) specified by the icons. For sake of reference, the crossed-swords indicates the attack button, each of the plain arrow keys indicates a movement button, an upward arrow with a series of horizontal lines beneath indicates the jump button and the plus sign is a separator. In light of this, the symbols may be interpreted to mean that activating The Dream is done by pressing the attack button, then depressing simultaneously the up and right movement keys.
Note well: there seems to be no hard and fast rule about when the various steps of the sequence must be completed. It seems to vary from weapon to weapon. I chose the Elf Sword for purposes of illustration because The Dream is relatively simple to activate and does a pretty fair amount of damage. In contrast, the Queen's Sword, one of the special weapons in the game, took much more practice on my part before I could consistently use its weapon-specific combo. Whenever the player finds a new weapon, a small icon will appear in the lower right corner of the screen, suggesting that the player activate his journal. Heed this icon! When you find a new weapon, take a moment or two to review the various attacks of which the weapon is capable. Each weapon in Blade of Darkness has its own feel and requires a certain amount of practice to use well. When practicing each combo, the name of the attack will appear at the bottom of the screen the very first time it is successfully activated. Further, a bright red trail will be left throughout the weapon's arc of motion.
Somewhat similar to the weapons page is the abilities page, which is shown below. The primary difference is that the character-specific abilities displayed on this page may be used with any of the weapons specified, regardless of whether the weapon has its own combo, etc. There are a few caveats to this rule, however, as some of the most unique weapons in the game seem just too much for certain characters to handle. Without spoiling anything, let me point out that after Sargon killed a particularly nasty boss-like bad guy in the very last level of the game, I was surprised to discover that the sword he dropped could not be used with any of the character-specific abilities. When I tried, Sargon gasped like a fish out of water. Perhaps the sword was really a two-handed sword in disguise!

At any rate, the above illustration of the abilities page is far "cleaner" than the weapons page. A total of nine different character-specific abilities are listed above, which again belong to Sargon. For each entry, the box to the far left describes the general class of weapon with which the ability may be used. The name of the character-specific ability then appears at the top of the box to the immediate right, beneath which appears the same sort of iconic representation and level specification that appear on the weapons page. Again for sake of reference, the crossed-swords indicates the attack button, each of the plain arrow keys indicates a movement button, an upward arrow with a series of horizontal lines beneath indicates the jump button and the plus sign is a separator. So for example, the player may activate Sargon's Left Dodge Attack by simultaneously pressing the jump and move left buttons followed at just the right time by pressing the attack button. As with the weapon-specific combos, the name of the attack will appear at the bottom of the screen the very first time it is successfully activated. Further, a dimly yellow trail will be left throughout the weapon's arc of motion. Click here to view Zoe's abilities page or Nagflar's abilities page.
The items page confused me initially because I was thinking of it as an inventory page. Blade of Darkness has just enough role-playing elements (e.g., experience and experience levels, skills that are unlocked via progress, etc.) that I was thinking of this page incorrectly. Let's be clear: the items page does not show what items your character is carrying. Rather, it shows information about all of the items in the game that are of most interest to your character. And as near as I can tell, this page is always the same no matter which character is being played.

The above illustration shows, for example, that consuming a package of travel rations not only restores 100 health, it also cures any poisonous infection. Similarly, if the character is lucky enough to find and be carrying a crown, then he may activate its fire resistance at any point by selecting the item in his inventory and using it. To my knowledge, none of the items confer their benefits simply by being carried. Rather, they must all be used in order to have any effect.
The texts page, displayed below, shows the minimal information provided about the current level, taken generally from the cut-scene at its beginning. This is essentially just a reference for the player to be able to reacquaint himself with the story line and immediately relevant goals therein. In all honesty, though, this information is generally not all that useful. Most players will likely be able to figure out precisely what needs to be done from the clues in the game environment. For sake of reference, the following text is taken from the very last, semi-secret level of the game, The Abyss.

The secrets page, displayed below, gives a bit of explanation about and the symbols used for the six runes that the player may find during his adventures. Finding the runes is not essential to the game, though it is very helpful. The primary payback for finding all six runes is that the Sword of Ianna is more useful along lines I will not divulge. Also, if the player has collected all six runes, then he will be allowed into The Abyss; otherwise, the game will end upon his defeating Dal Gurak. Many players find this an unsatisfying end to the game insofar as defeating this faux-ultimate boss results in nothing more special than seeing the credits. Be sure to collect all six runes! The Abyss is not to be missed, and the final cut-scene is really worth the rather copious additional effort required to make it there.
