Circle 5 of the theme is a Greater stone Lizard. It is weaker than the 4th circle theme, the Stone Oxen thing.
The Stone Ox has:
1. Mind immunity
2. Immunity to paralysis
3. Immunity to critical hit/sneak attack.
The circle 5 summon, the Greater Stone Lizard
1. Has slightly more damage/AB/HP
2. None of the above immunities.
I recommend the circle 5 summon be changed to a Greater Stone Ox which could simply be the same as a circle 4 ox, but with Damage reduction?
Correction, it's called Summoned Earth Elemental Oxen