Declare Altaïr as an attacker, triggering its ability, creating two tapped and attacking copies of Éomer.
Put all but one Éomer token into your graveyard due to the legend rule, causing you to get at least one Éomer trigger, causing you to untap all creatures you control and to get an additional combat phase after this one.
At the end of your combat phase, Altaïr triggers, causing you to exile the Éomer token.
Repeat each combat phase.

Infinite creature LTB

Infinite creature ETB

Infinite death triggers

Infinite combat phases

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Altaïr Ibn-La'Ahad

Éomer, Marshal of Rohan

The Animus

Mondrak, Glory Dominus

At the beginning of your combat phase, Gogo triggers, causing it to become a copy of Altaïr with its name not changing, and causing both Gogo and Altaïr to get +2/+0 and haste until end of turn.
Declare Gogo and Altaïr as attackers, triggering their abilities.
Resolve the Altaïr trigger, creating a tapped and attacking copy of Éomer.
Resolve the Gogo trigger, creating a tapped and attacking copy of Éomer.
Put either Éomer token into your graveyard due to the legend rule, triggering the other Éomer token, causing you to untap all creatures you control and to get an additional combat phase after this one.
At the end of your combat phase, Altaïr triggers, causing you to exile the Éomer token.
Repeat from step 2 each combat phase.

Gogo, Mysterious Mime

Declare Redoubled Stormsinger and Altaïr as attackers, triggering their abilities.
Resolve the Altaïr trigger, creating a tapped and attacking copy of Éomer.
Resolve the Redoubled Stormsinger trigger, creating a tapped and attacking copy of Éomer.
Put either Éomer token into your graveyard due to the legend rule, triggering the other Éomer token, causing you to untap all creatures you control and to get an additional combat phase after this one.
At the end of your combat phase, Altaïr triggers, causing you to exile the Éomer token.
Repeat each combat phase.

Redoubled Stormsinger

Combos with "The Animus"