We'll, if he's criting on an 18-20, an avenger will crit 28% of the time, as stated by Iron Sky.
Now, with twin weapon fighting, that does become a 40% chance of getting one crit, and an 8% chance of getting 2 (for a total of a whopping 48% chance of critting). Again, as Iron Sky said.
Which really is pretty fantastic... making it a pretty good build no matter the strength of the avenger provided that the avenger hits the target with a roll of 18.
One needs to be a half-elf, though, which doesn't help the OP.
Incidentally, Darklord - any particular reason you want to go twin strike? Is if just for the gaming advantages of getting to reroll 2 attacks/round, or is there some additional reason?
Well, basically I was going for the crit fishing/extra damage. Right, the extra rolls and percentage increase for crits.
I was hoping the DMs would just let me switch to Half-Elf from Human but they won't. I don't know if you've seen some of my earlier posts in another threads about our DMs but we started out this campaign under 4e, and we were allowed to buy from the AV, up to our level, but not Artifacts or Wondrous Items, if we had the gold. Then, one item caused a total upset to one DMs plotline and they then cut the AV off from us totally - no magic shops in any town, no magic drops from encounters, etc, etc,. We've gotten nothing but gold and exp in the last 10 encounters or so. So we're stuck with what we've got right now. I've got a Craghammer, and was going to beg them to let me just get a throwing hammer for the 2nd melee item.
Point is, by the time we get to 11th/Paragon level, my choices are going to be very limited as far as options go. I can go Student of Caiphon or Radiant servant, to try to get my increased crit range, but I don't have, nor expect to be able to get, a Radiant weapon. I also won't be able to change weapons, so I can't go for Jagged on a sword or axe later on.
I was hoping that with Twin Strike, one of the PP paths like SOC or RS, and using Radiant/Fear powers, I could come up with some fair DPS via the increased chance of crits.
They ruled out the easiest path for me for that via Half-elf and versatile master though, thus my original post/questions.
I had taken the pains to write a great tie-in story too...and they even said it was "great!" but no, you can't switch.
