B · Engine & Sequencing · §12
The correct copy depends on location and intended conversion — Fragmented for value, Herald for movement.
What the copy gains
Move trigger (top three, may draw a unit) plus the Deathknell deploy — ignoring Energy.
What it does not gain
A Legend Reflection starts at the battlefield and misses the movement trigger entirely.
Best conversion outlet
Temporary death → deploy from hand; pay the Power
From the guide — §12 Copy Target Hierarchy
Karthus — correct only when you can exploit the additional multiplier immediately. A Karthus Reflection that merely sits until Temporary is usually worse than copying a Deathknell payoff; one preceding several simultaneous or controlled deaths can be exceptional.
Rift Herald — good when you specifically want the Deathknell. A Legend Reflection appears at the battlefield, so it misses Herald’s movement trigger. It is still a seven-Might body whose Temporary death can deploy an expensive unit from hand.
Rift Herald — one of the highest-ceiling Mirror lines: ready Reflection at base → move (top-three look, may draw a unit) → Temporary death → Deathknell deploys from hand ignoring Energy. With Karthus, the death can produce two Herald triggers, provided legal units and the necessary Power.
Vi — Mirror does not reproduce Ambush as a play event, but the copied Vi retains its attack-triggered Stun. A ready Vi at base can create an immediate scoring swing.
Harnessed Dragon and Watcher — usually terminal or emergency copies. You receive the large body but not the play trigger. Copy them when raw Might itself is the relevant resource, not when you need removal or a board-wide debuff.