Hello OP
Steelskull is a solid mid game (used to be end game about a year ago) CB champ
In fact he is actually really good in faction wars and mid game dungeons, very decent utility
back to cb, if you want to use him there I would suggest looking into 4:3 turn ratio comps, as a fully booked ss will make him have a 4 turn cd ally def up, which you want to be up on both cb aoe hits
his poison proc chance is fairly low, but would suggest giving him master hexer and sniper to help with that
who else you planning on running him with?
good luck!
I run a Skulltower comp, SC lead, Tower, Fayne, BEK and Fatboi, its an easy 1 key NM and 2 key UNM.
With Septimus in the flex spot you will be wrecking the ranch.
I have a skulltower comp that i do almost 30mil singel Key i was looking for a second team to experment with thsts where steelskull comes in at