Blightsteel Colossus

Bracket

• B1 Exhibition — Not in the same deck as its two-card combo partners: Cybermen Squadron, Chandra's Ignition, Blade of Selves, Legion Loyalty, Duke Ulder Ravengard
• B2 Core — Not in the same deck as its two-card combo partners: Cybermen Squadron, Chandra's Ignition, Blade of Selves, Legion Loyalty, Duke Ulder Ravengard
• B3 Upgraded — Not in the same deck as its early two-card combo partners: Cybermen Squadron, Chandra's Ignition, Blade of Selves, Legion Loyalty, Duke Ulder Ravengard
• B4 Optimized — allowed: No restriction beyond the banned list
• B5 cEDH — allowed: No restriction beyond the banned list

Why

• Two-card combo with Cybermen Squadron, Chandra's Ignition, Blade of Selves, Legion Loyalty, Duke Ulder Ravengard (early with Cybermen Squadron, Chandra's Ignition, Blade of Selves, Legion Loyalty, Duke Ulder Ravengard)

How Lotus Vault estimates a bracket

Bracket: Lotus Vault analysis, with Commander Spellbook flags

Combos

23 known combos, 5 of them two-card.

• Cybermen Squadron + Blightsteel Colossus
  Produces: Each opponent loses the game
  View on Commander Spellbook
• Blightsteel Colossus + Chandra's Ignition
  Produces: Each opponent loses the game
  View on Commander Spellbook
• Blightsteel Colossus + Blade of Selves
  Produces: Each opponent loses the game
  View on Commander Spellbook

Combos: Commander Spellbook

Rulings

• 2020-08-07 · Wizards of the Coast
  Damage from a source with infect is damage in all respects. If the source with infect also has lifelink, damage dealt by that source also causes its controller to gain that much life. Damage from a source with infect can be prevented or redirected. Abilities that trigger on damage being dealt will trigger if a source with infect deals damage, if appropriate.
• 2020-08-07 · Wizards of the Coast
  Damage that a creature with infect deals doesn't result in damage being marked on a creature or a player losing life. Instead, it results in that many -1/-1 counters being put on that creature or that many poison counters being given to that player. Damage dealt to planeswalkers still results in that planeswalker losing that many loyalty counters.
• 2020-08-07 · Wizards of the Coast
  The -1/-1 counters remain on the creature indefinitely. They're not removed if the creature regenerates or the turn ends.
• 2020-08-07 · Wizards of the Coast
  A player who has ten or more poison counters loses the game. This is a state-based action.

Rulings: Scryfall · Wizards of the Coast