Cast Karmic Guide by paying {3}{W}{W}.
When Karmic Guide enters, it triggers, targeting Sister Hospitaller.
Holding priority, activate Viscera Seer by sacrificing Karmic Guide.
Resolve the Karmic Guide ability, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters, it triggers, targeting Karmic Guide.
Holding priority, activate Viscera Seer by sacrificing Sister Hospitaller.
Resolve the Sister Hospitaller ability, returning Karmic Guide from your graveyard to the battlefield and causing you to gain 5 life.
Repeat from step 2.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite scry 1

Infinite lifegain triggers

Infinite lifegain

Karmic Guide

Sister Hospitaller

Viscera Seer

Cast Sister Hospitaller by paying {4}{W}{B}.
When Sister Hospitaller enters, it triggers, returning Fiend Hunter from your graveyard to the battlefield and causing you to gain life equal to its mana value.
When Fiend Hunter enters, it triggers, exiling Sister Hospitaller.
Activate Ashnod's Altar by sacrificing Fiend Hunter.
When Fiend Hunter dies, it triggers, returning Sister Hospitaller from exile to the battlefield.
Repeat from step 2.

Infinite colorless mana

Ashnod's Altar

Fiend Hunter

Activate Viscera Seer by sacrificing Sister Hospitaller.
When Sister Hospitaller dies, Body Launderer's first ability triggers, causing Body Launderer to connive.
Resolve the Viscera Seer ability.
Activate Viscera Seer by sacrificing Body Launderer.
When Body Launderer dies, its second ability triggers, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters, it triggers, returning Body Launderer from your graveyard to the battlefield and causing you to gain 4 life.
Resolve the Viscera Seer ability.
Repeat.

Infinite self-discard triggers

Near-infinite lifegain

Near-infinite lifegain triggers

Near-infinite ETB

Infinite draw triggers

Infinite looting

Near-infinite LTB

Near-infinite death triggers

Near-infinite sacrifice triggers

Body Launderer

Activate Viscera Seer by sacrificing Sister Hospitaller.
Activate Viscera Seer by sacrificing Junji.
When Junji dies, it triggers, returning Sister Hospitaller from your graveyard to the battlefield and causing you to lose 2 life.
When Sister Hospitaller enters the battlefield, it triggers, returning Junji from your graveyard to the battlefield, and causing you to gain 5 life.
Resolve the Viscera Seer ability from step 2.
Repeat.

Junji, the Midnight Sky

Cast Sister Hospitaller by paying {4}{W}{B}.
When Sister Hospitaller enters, it triggers, returning Abdel Adrian from your graveyard to the battlefield and causing you to gain life equal to its mana value.
When Abdel Adrian enters, it triggers, exiling Sister Hospitaller until Abdel Adrian leaves the battlefield and creating a 1/1 Soldier creature token.
Activate Viscera Seer by sacrificing Abdel Adrian.
When Abdel Adrian leaves the battlefield, Sister Hospitaller is returned from exile to the battlefield.
Repeat from step 2.
Resolve all Viscera Seer abilities.

Infinite creature tokens

Infinite blinking of nonland permanents you control

Abdel Adrian, Gorion's Ward

Activate Warren Soultrader by paying 1 life and sacrificing Sister Hospitaller, creating a Treasure token.
Activate Warren Soultrader by paying 1 life and sacrificing Junji.
When Junji dies, it triggers, returning Sister Hospitaller from your graveyard to the battlefield and causing you to lose 2 life.
When Sister Hospitaller enters the battlefield, it triggers, returning Junji from your graveyard to the battlefield and causing you to gain 5 life.
Resolve the Warren Soultrader ability from step 2, creating a Treasure token.
Repeat.

Infinite colored mana

Infinite Treasure tokens

Warren Soultrader

Activate Sidisi by tapping it and sacrificing a nontoken creature with mana value 5.
When the creature dies, Sidisi triggers, untapping Sidisi.
Resolve the Sidisi ability, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters the battlefield, it triggers, returning the creature with mana value 5 from your graveyard to the battlefield and causing you to gain 5 life.
Activate Umbral Collar Zealot by sacrificing Sister Hospitaller.
When Sister Hospitaller dies, Sidisi triggers, untapping Sidisi.
Resolve the Umbral Collar Zealot ability.
Repeat.

Infinite surveil 1

Sidisi, Regent of the Mire

Thornbite Staff

Umbral Collar Zealot

Activate Sidisi by tapping it and sacrificing Zealous Conscripts, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters the battlefield, it triggers, returning Zealous Conscripts from your graveyard to the battlefield and causing you to gain 5 life.
When Zealous Conscripts enters the battlefield, it triggers, untapping Sidisi.
Activate Umbral Collar Zealot by sacrificing Sister Hospitaller.
Repeat.

Zealous Conscripts

Activate Vampire Hexmage by sacrificing it, removing all counters from Invasion of Arcavios.
Invasion of Arcavios triggers, causing you to exile it and cast it as Invocation of the Founders.
Activate Chandra's first ability by putting a loyalty counter on it, adding {1}{W}.
Cast Flicker by paying {1}{W}, targeting Invocation of the Founders.
Chandra and Invocation of the Founders trigger, copying Flicker twice, with one copy targeting Chandra and the other targeting Sister Hospitaller.
Resolve the first Flicker copy, blinking Chandra.
Resolve the second Flicker copy, blinking Sister Hospitaller.
When Sister Hospitaller enters the battlefield, it triggers, returning Vampire Hexmage to the battlefield from your graveyard and causing you to gain 2 life.
Resolve the original Flicker, blinking Invocation of the Founders, causing it to enter the battlefield as Invasion of Arcavios.
When Invasion of Arcavios enters the battlefield, it triggers, returning Flicker to your hand from your graveyard.
Repeat.

Combos with "Sister Hospitaller"