Ekko, Recurrent

Ekko, Recurrent reads, "[Deathknell][] Recycle me to ready your runes." Deathknell is functionally short for "When I die, ..." We can translate this to our sequence as "When I die, recycle me to ready your runes." "Recycle me to" is a cost within instructions that appears where we would expect it to based on our sequence, so it becomes the base cost of the ability when it is placed on the chain and is not part of the effect. The ability can be split into "When I die, recycle me to" and "ready your runes."

383.3.b. If a Triggered Ability contains a cost within instructions at the beginning of the effect or immediately following the "you may" or "they may" that appears as the first part of the effect, that cost is treated as the base cost of the Triggered Ability. Example: Ekko, Recurrent reads "[Deathknell][] Recycle me to ready your runes." In this case, "recycle me to ready your runes" is a cost within instructions that appears at the beginning of the effect of the ability, and thus "recycle me" is taken as the base cost of the triggered ability. Example: Insightful Investigator reads "When you play me, choose an opponent. They reveal their hand. You may pay 2 XP to choose a card from their hand. If you do, they discard that card and draw 1." The "pay 2 XP" is a cost within instructions, but because it does not appear in the first part of the effect, it is not taken as the base cost of the triggered ability. Paying 2 XP is performed on resolution.