I really don't know to how to use karnage yet and my build is average at best, still does well.
The dude does A LOT. I just leave him on the reverse side for bosses.
For PvP, I'm a big fan of the TM steal into flip and boom. But you have to not just kill them to get that TM, although if you don't the surviving enemy is usually all locked out anyhow.
I just tried updating to randomly upgrade an accessory from level 15 to 16. It displayed 31k as a cost. I had 730,000 plarilyum coins from selling random artifacts and accessories.
It cost me over 700,000k plarium points for a single random generated roll to upgrade the artifact. This wzs a computer error i have been saving plarium to upgrade a character to level 60 with a ham joint not a level5 chicken. I cannot see how to contact a referee to get a refund for plarium lost.