If I have Kog'Maw and another 1M unit at a battlefield, kill Kog'Maw to pay for Cruel Patron's cost, and play Cruel Patron to that battlefield, will Cruel Patron be recalled to my base when Kog'Maw's Deathknell triggers during cleanup?

Ruling: No, Cruel Patron will not be recalled. Cruel Patron will take the damage from Kog'Maw's Deathknell trigger and remain on the battlefield.

Sequence:

• When you pay the cost for Cruel Patron (killing Kog'Maw), Patron is already on the chain in a pending state trying to finalize
• Kog'Maw's Deathknell trigger goes onto the chain above Patron
• Patron auto-resolves off the chain as a finalized permanent before you finalize Kog'Maw's Deathknell ability
• Nothing can enter the chain below Patron once he is pending and trying to finalize
• When Kog'Maw's Deathknell resolves, Patron is already on the battlefield and takes the damage