Holding priority, activate Drafna's second ability by paying 3 and tapping it, copying the Su-Chi Cave Guard spell.
Resolve the copy of the Su-Chi Cave Guard spell.
Activate Ashnod's Altar by sacrificing the Su-Chi Cave Guard token, adding CC.
When the token Su-Chi Cave Guard dies, it and Drafna trigger.
Resolve the Su-Chi Cave Guard trigger, adding eight C.
Resolve the Drafna trigger, untapping it.
Repeat from step 2.
This clever loop turns Drafna, Founder of Lat-Nam's ability to copy artifact spells into a mana-positive engine by exploiting the massive refund provided by Su-Chi Cave Guard. As you sacrifice the token copy to Ashnod's Altar, the Cave Guard's death trigger generates eight colorless mana to easily fuel the repetition, while Thornbite Staff stands ready as an alternative tool to untap your key pieces or weaponize those dying creatures if the board state demands it.