Does Commander Ledros's cost reduction effect trigger if a unit survives being killed (e.g., through Soraka's effect)?

Question

Accepted Answer

Yes. If you choose to kill friendly units as Commander Ledros's optional additional cost, the cost reduction applies even if those deaths are replaced or the units “survive” (for example via Soraka) because the additional cost is still considered paid when replacement effects substitute the death. [356.2.b.1] [356.4.c] [357.2.a] [356.4.f.1]

When playing Commander Ledros you declare in step 2 whether you will pay the optional additional cost of killing any number of friendly units; the cost reduction is applied when that additional cost is added to the spell’s cost. During payment, if a replacement effect (e.g., a Soraka-style “if a friendly unit would die, do X instead”) replaces the unit’s death, the kill cost is still considered paid and the reduction still counts for each unit you chose to kill. [356.2.b.1] [356.4.c] [357.2.a] [356.4.f.1]

Declare during step 2 that you will pay Commander Ledros's optional additional cost to kill any number of friendly units; this declaration makes the optional costs part of the spell’s cost to be adjusted by discounts [356.2.b.1] [356.4.c]. Apply any discounts that affect the added component (the kill cost and the spell’s costs) when that additional cost is added to the total cost [356.4.c]. In the Pay Costs step, perform the non-standard cost (attempt to kill the chosen friendly units). If a replacement effect replaces those deaths (e.g., a Soraka effect that heals/recalls instead), the attempt is still considered paying the cost [357.2.a] [FAQ:unleashed#4]. Because the optional additional cost was chosen/paid, the cost reductions from killing those units apply even if the actual deaths were replaced or the units 'survived' [356.4.f.1] [357.2.a].

If you choose to kill zero units, you get no reduction — choosing to pay nothing is a legal choice under the 'may' clause [356.2.b.1]. If paying the chosen kill(s) would deterministically make later required choices illegal, you cannot choose that during payment (see rule 357.3); e.g., you cannot choose to kill the only unit that must be targeted later if that would make the action illegal [357.3]. If an effect specifically prevents the additional-cost payment from being attempted (not merely replacing its result), that could stop the reduction; the ruling above only covers replacement-of-death situations like the Zhonya’s Hourglass example where the cost was still considered paid [357.2.a]. If the card used "if you do" rather than "as an additional cost," the interaction would be different — Ledros uses an 'as an additional cost' template, so it functions as a cost and behaves as described [FAQ:unleashed#4].

The text on Commander Ledros is an optional additional cost that reads "As you play me, you may kill any number of friendly units as an additional cost. Reduce my cost by [Order] for each killed this way." That makes the kill action a non-standard, optional additional cost to play the unit [356.6] [356.2.b.1]. Per the play sequence, you declare in step 2 that you will pay this optional cost; when that additional cost is added to the spell’s cost any discounts that apply to that component are applied at that time [356.2.b.1] [356.4.c]. When you go to actually pay the non-standard cost in the Pay Costs step, you attempt to kill the chosen units. If a replacement effect substitutes some other event for the death (for example, a Soraka-style effect or the Zhonya’s Hourglass example), the rules explicitly state that costs which are replaced by replacement effects are still considered paid, and the player can continue resolving the play [357.2.a]. The clarifying FAQ also states broadly that costs do not care if the game action is replaced, as long as an attempt was made to perform it [FAQ:unleashed#4]. Finally, the rules make clear that an optional additional cost counts as 'paid' if the player chose to pay it, regardless of how much was actually paid after discounts [356.4.f.1]. Putting that together: if you chose to kill N friendly units as Commander Ledros's additional cost, you get the cost reduction for N units even if replacement effects cause those units to 'survive' or be substituted during payment. Exceptions would be effects that prevent the cost from being attempted or make choosing that cost illegal at the time it must be declared (see rule [357.3] for not making deterministically illegal choices).