Sin, Unending Cataclysm | Thornbite Staff | Phyrexian Altar

(and one other card)

Sin in hand or in the command zone.
All other permanents on the battlefield (
Thornbite Staff attached to
Selvala and
Selvala without summoning sickness).
Sin must be your commander.

There are at least X counters on artifacts, creatures and/or enchantments you control, where X is 2 plus the number of times you've cast
Sin from the command zone this game.

({5} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) plus commander tax if applicable available.

Cast
Sin either from your hand or command zone by paying ({5} magic symbol) ({G} magic symbol) ({U} magic symbol) plus commander tax if applicable.
As
Sin enters, remove all counters from all artifacts, enchantments and creatures you control, putting twice that many +1/+1 counters on
Sin.
Activate
Selvala by paying ({G} magic symbol) and tapping it, adding at least ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) plus an additional ({X} magic symbol) equal to
Sin's power minus 3.
Activate
Phyrexian Altar by sacrificing
Sin, adding ({1} magic symbol) .
Choose to return
Sin to the command zone from your graveyard.
When
Sin dies, it and
Selvala trigger.
Resolve the
Sin trigger, putting its counters on
Selvala.
Resolve the
Selvala trigger, untapping it.
Activate
Selvala by tapping it, adding an amount of ({G} magic symbol) or ({U} magic symbol) equal to its power.
Repeat.