At the beginning of your end step, return a land you control to its owner's hand.
Zell is a mono-red landfall Voltron threat: ramp out as many lands as possible to swell his power, then crack through for lethal commander damage. The forced end-step land bounce is actually an engine—replay lands to trigger landfall payoffs every turn while keeping Zell's attack high. You play extra lands, abuse landfall and land-return triggers, and close games with a giant evasive Monk.
Commander power scales for free with your land count, hitting 21 commander damage fast
Built-in extra land drop accelerates you ahead of the table
The mandatory end-step bounce becomes free recurring landfall fuel rather than a true drawback
Cheap three-mana body means he comes down early and recasts easily
Mono-red has poor enchantment/artifact removal and limited card advantage
Voltron is fragile to a single removal spell, bounce, or chump-block wall
No native evasion or trample—Zell can be blocked or stonewalled by big toughness
Bouncing a land each turn can stall mana if you don't have plays to dump, and missing land drops shrinks him
Vulnerable to wrath effects and edict removal that punish a one-creature plan