B · Engine & Sequencing · §8
The probabilistic problem is the ratio of bodies to support, not assembling a combo.
The deck is not trying to assemble a deterministic combo. Its consistency question is whether a given opening has the right ratio of bodies to support, and the numbers say protection is much easier to find than a body.
P(≥1 early unit in 4) = 1 − C(28,4) / C(39,4) ≈ 75.1%
P(≥1 true two-drop in 4) = 1 − C(31,4) / C(39,4) ≈ 61.7%
P(≥1 protection card in 4) ≈ 81.8%
P(early unit AND protection) ≈ 58.6%
P(≥1 Irelia, Fervent in 4) ≈ 28.4%
Tempered is always available at four Energy; Fervent is the drawn high-ceiling threat at roughly one opening hand in four. The deck should function without Fervent. When she appears she raises the ceiling rather than rescuing a shell that was not working.
The sideboard is seven units to three spells on purpose. Most post-board configurations improve threat quality while holding or increasing unit density, and when Whiteflame or leaves, a sideboard unit should usually take the slot.