Activate Terra, Magical Adept by paying {4}{R}{G} and tapping it, exiling it and returning it to the battlefield as Esper Terra.
When Esper Terra enters the battlefield, its first chapter ability triggers, creating a token copy of Mesmerizing Dose.
When the Mesmerizing Dose token enters the battlefield, it triggers, putting a lore counter on Esper Terra.
Repeat from step 2 two additional times, from Esper Terra's second and third chapter abilities triggering.
Esper Terra's fourth chapter ability triggers, causing you to add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, and then exile Esper Terra and return it to the battlefield as Terra, Magical Adept.
When Terra, Magical Adept enters the battlefield, it and Obsidian Battle-Axe trigger.
Resolve the Terra trigger, causing you to mill five cards and return up to one enchantment card from among them from your graveyard to your hand.
Resolve the Obsidian Battle-Axe trigger, attaching it to Terra.
Repeat.

Infinite creature LTB

Infinite creature ETB

Infinite colored mana

Infinite self-mill

Infinite proliferate

Terra, Magical Adept // Esper Terra

Mesmerizing Dose

Obsidian Battle-Axe

Activate Terra, Magical Adept by paying {4}{R}{G} and tapping it, causing you to exile it and return it to the battlefield as Esper Terra.
As Esper Terra enters the battlefield, choose to have it enter with four lore counters due to its read-ahead ability.
Esper Terra's fourth chapter ability triggers, causing you to add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, and then exile Esper Terra and return it to the battlefield as Terra, Magical Adept.
When Terra, Magical Adept enters the battlefield, it and Obsidan Battle-Axe trigger.
Resolve the Terra trigger, causing you to mill five cards and put up to one enchantment card milled this way into your hand.
Resolve the Obsidian Battle-Axe trigger, attaching it to Terra.
Repeat.

Barbara Wright

Cast Fireblade Charger by paying {R}.
Fireblade Charger enters the battlefield, triggering Obsidian Battle-Axe, attaching it to Fireblade Charger.
Activate Phyrexian Altar by sacrificing Fireblade Charger, adding {R}.
Fireblade Charger dies, triggering itself and Koll.
Resolve Fireblade Charger's trigger, dealing 3 damage to any target.
Resolve Koll's trigger, returning Fireblade Charger from your graveyard to your hand.
Repeat.

Infinite damage

Infinite death triggers

Infinite creature sacrifice triggers

Infinite storm count

Koll, the Forgemaster

Phyrexian Altar

Fireblade Charger

Cast Grim Initiate by paying {R}.
Grim Initiate enters the battlefield, triggering Obsidian Battle-Axe, attaching it to Grim Initiate.
Activate Phyrexian Altar by sacrificing Grim Initiate, adding {R}.
Grim Initiate dies, triggering itself and Koll.
Resolve Grim Initiate's trigger, amassing 1.
Resolve Koll's trigger, returning Grim Initiate from your graveyard to your hand.
Activate Phyrexian Altar by sacrificing the Zombie Army token, adding one mana of any color.
Repeat.
Once you have infinite mana, you may repeat the loop without sacrificing the Zombie Army token.

Infinitely large creature

Grim Initiate

Cast Goblin Fireslinger by paying {R}.
Goblin Fireslinger enters the battlefield, triggering Obsidian Battle-Axe, attaching it to Goblin Fireslinger and giving it haste.
Activate Goblin Fireslinger by tapping it, dealing 1 damage to target player.
Activate Phyrexian Altar by sacrificing Goblin Fireslinger, adding {R}.
Koll triggers, returning Goblin Fireslinger from your graveyard to your hand.
Repeat.

Goblin Fireslinger

Cast Mogg War Marshal by paying {1}{R}.
Mogg War Marshal enters the battlefield, triggering itself and Obsidian Battle-Axe.
Resolve Obsidian Battle-Axe's trigger, attaching it to Mogg War Marshal.
Resolve Mogg War Marshal's trigger, creating a 1/1 Goblin creature token.
Activate Phyrexian Altar twice by sacrificing the Goblin token and Mogg War Marshall, adding {R}{R}.
Mogg War Marshall dies, triggering itself and Koll.
Resolve Mogg War Marshal's trigger, creating another 1/1 Goblin creature token.
Resolve Koll's trigger, returning Mogg War Marshal from your graveyard to your hand.
Repeat.
Once you have infinite creature tokens, you may activate Phyrexian Altar any number of times to add infinite mana.

Infinite creature tokens

Mogg War Marshal

Cast Spear Spewer by paying {R}.
Spear Spewer enters the battlefield, triggering Obsidian Battle-Axe, attaching it to Spear Spewer and giving it haste.
Activate Spear Spewer by tapping it, dealing 1 damage to each player.
Activate Phyrexian Altar by sacrificing Spear Spewer, adding {R}.
Koll triggers, returning Spear Spewer from your graveyard to your hand.
Repeat until all opponents with a lower life total than your own have lost the game.

Combos with "Obsidian Battle-Axe"