Probably not. She'll fully become Bastet, and then that will probably cause some issue that Karna resolves, and then they beat the humans, and then go after whatever outer god they dealt with earlier on. THEN, it ends. Probably 2 or 3 more arcs, which means basically any length given how inconsistent this series is with arc length
Still don't think that's Sloth (a piece of Bastet), unless Nyar ate him or used him as a body to invade the world or something. Nyar fought the old gods directly from before they entered this world.
And the promise is over, since old man Hercules died (and was reincarnated).