EyeontheMountain said:
The way I see it is if they are listed as large weapons, medium sized characters cannot use them one handed.
That's 3E mechanics; in 3.5, they're all listed as 'Two-Handed Weapons', which can be Small, Medium, Large, or whatever.
The answer to this question was actually clearer in the 3E PHB, because it was assumed that all weapons being described (for the most part) were sized for a Medium creature, so it was easier for them to give an example. But the rules are still trackable in 3.5.
We know three things:
1.
Two hands are required to use a two-handed melee weapon effectively.
2.
The measure of how much effort it takes to use a weapon (whether the weapon is designated as a light, one-handed, or two-handed weapon for a particular wielder) is altered by one step for each size category of difference between the wielder’s size and the size of the creature for which the weapon was designed.
3.
A creature wielding a double weapon in one hand can’t use it as a double weapon—only one end of the weapon can be used in any given round.
Let's say we have a human (a Medium creature) with a Medium two-bladed sword (a two-handed weapon, and a double weapon).
Does point 3 mean that he can wield it in one hand, because it is a double weapon? No; point 3 tells us the consequences of wielding a double weapon in one hand, but it does not give you permission to do so if another rule prevents it. And in this case, another rule does; for the human, the two-bladed sword is a two-handed melee weapon, and point 1 tells us that he requires two hands to use it. Point 3 is true but irrelevant; since he cannot wield it in one hand, the rule does not matter to him.
Now let's say an ogre (a Large creature) takes the same Medium two-bladed sword. Point 2 tells us that since the ogre is one size category larger than the sword, it is treated as a one-handed weapon instead of a two-handed weapon for him. So, for the ogre in this case, point 1 does not apply; the sword is not a two-handed weapon. Thus, he can wield it in one hand. What happens in this case? Point 3 tells us that he can do so, but he can only use one end in a given round.
Similarly, the human could use any Small double weapon (such as a hooked hammer sized for a gnome) in one hand, but could only use one end each round.
-Hyp.