Chain attack should grant you the effects of stoneskin while it is active during a chain attack
You should get 100 temporary hitpoints that fade after the chain attack is done.
Your chain attack should gain a 10% chance to inflict your targets with negative levels!
Your chain attack should leave you with a nulmagic aura for the next 20 seconds after the chain attack is complete.
And you should automatically gain immunity to energy drain spells at level 20!
They should be racial feats automatically granted at level 20.
Sealed Soul
Enhanced Chain Attack