Let’s come up with a monster.

I propose the Demiourg unit – there is only one on the map, and it can only be recruited in one dwelling. After purchasing the Demiourg, the dwelling disappears. It's like a unit-god. Energy – 120,000 XP, Attack Power – from 12,700 to 38,000, Mana – infinite, like a phoenix, with 2 resurrections. Immune to Light and Darkness magic. To recruit, it costs 500,000 gold and 500 of each type of resource, plus the Tear of Ash. It looks like a Titan. After the Demiourg is defeated, it reappears in the dwelling, which also reappears. It is infinite.