Spoilers perhaps
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Easier is to tell what level you are. I have taken him on with chars (party) where levels are from 7 to 12. 2 days ago did smack him with my paladin char and his party, levels were from 8 to 12. Some take him on maybe even earlier, some later. Main things really is whether you have the spells to resist it's attacks of fire, lower it's resistances and such. Nothing really too high level of spells is needed, so if someone tells you about Time Stop and Abi-Dalzims and such then just ignore it, it's a waste, can be done with spells and gear of much lower lvl. 2-3 tank types are good, summons too as a cannon fodder, spread the party around the Kraggie. And so on
Tell your level and the level of your party members and then it's much easier to say.