How can you create a combo with Preston, the Vanisher, Karmic Guide, Breath of Life, Phyrexian Altar?
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[START OF COMBO]This combo can be formed with Preston, the Vanisher, Karmic Guide, Breath of Life, Phyrexian Altar

Color identity: W
Mana cost: {3}{W}
Steps:
  1. Cast Breath of Life by paying {3}{W}, returning Karmic Guide from your graveyard to the battlefield.
  2. Karmic Guide and Preston trigger.
  3. In response, activate Phyreixan Altar by sacrificing Karmic Guide, adding {W}.
  4. Resolve the Karmic Guide trigger, returning any creature from your graveyard to the battlefield.
  5. Resolve Preston's trigger, creating a 0/1 Illusion token copy of Karmic Guide.
  6. The token Karmic Guide enters the battlefield, returning the nontoken Karmic Guide from your graveyard to the battlefield.
  7. Repeat from step 2.
  8. Once you have infinite Illusion tokens and infinite mana, you may activate Preston any number of times.[END OF COMBO STEPS]

Result:
  - Exile any number of nonland permanents
  - Infinite colored mana
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite leaves the battlefield
  - Infinite sacrifice triggers[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Preston, the Vanisher must be on the battlefield
  - Karmic Guide must be in the graveyard
  - Breath of Life must be in your hand
  - Phyrexian Altar must be on the battlefield
[END OF COMBO PREREQUISITES]
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