Version 1.2.0
> Fixed version CVar
> No longer changes self damage
> Rewrote and renamed

Version 1.1.0
> Add reset server command
> Add team only cvar

Version 1.0.0
> Initial Release

Nice plugin, but a couple of things I wanted to point out which aren't critical, but just bother me a bit :wink:

You may want to add a loop in PluginStart to hook all players to account for late loading.

That one is something you'll probably want to do. The rest of these are basically just suggestions of what I'd do.

Ok first off...lolwut?
Anyway...

You should move the enabled check to before the attacker validity check.

Then, If you're doing this for each class:
Why not check it once then return?

In fact, because of short-circuiting, you could move all of those to the same check:
Also, why check if the damage <= 1.0? What if people want to lower damage with this with 0.5(half damage)?
I'd personally remove that altogether and have it just multiply the damage. Your cvars already limit it to a min of 0.0, so no need to check < 0.0 either. As for disabling, 1.0 is already 'disabled' really since it won't change the damage at all, and having it just multiply the damage by 1 seems faster than specifically checking for it just to return as normal.

Next point, I'd suggest checking and storing the attacker's class at the start rather than having to do it for each class.

Further, You could change the class checks into a switch for faster computing.

Actually, if you change the cvars a bit...

You know what? I'm rambling on a bit, let me just show an example, eh? :)