Whenever you scry, if Legolas is tapped, you may untap it. Do this only once each turn.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Legolas.
Legolas grows huge off opponents' creatures dying, then beats down as a repeatable attacker/blocker who can untap each time you scry. Build a removal-heavy GU midrange shell that kills opposing creatures (and benefits when you scry), turning every wrath, edict, and ping into counters on your commander before swinging in or going wide with fight/ping support.
Scales for free in creature-heavy multiplayer pods where things die constantly
Scry-untap lets Legolas attack and still block, doubling as a defensive wall with Reach
Pairs naturally with board wipes and edicts you already want to run
GU gives access to the best card advantage, ramp, and counterspells
Relies on opponents' creatures dying — stalls hard against creatureless control or token-light pods
No built-in evasion or trample, so a fat Legolas gets chump-blocked forever
Counters vanish to any removal, bounce, or board wipe, costing huge tempo
Slow to close games on its own without combat enablers