Yeah I tried that way before, with final ultimate weapon enemy profile. I tried today and he did not fly away, but there's still two problems.
First problem : his current HP = 20000.
Delete the AI script that sets Ultima Weapon's HP. Or, just change the value of 20,000 to whatever value you prefer.
And in the game basically two types of battles with ultimate weapon : aerial and ground battles, and I want create ground battles with him.(when his model is on the ground)
But it does not work for now.
In fact, there are also two Ultima Weapon enemy models, the one hovering and the one standing on the ground. So, you will have to copy the enemy model to create "ground battles".