Emerald Light can be used to heal Arcane Green Lantern himself. The mark is not consumed when it heals a champion. It will not go on cooldown if the basic attack deals the killing blow.
Arcane Green Lantern cannot cast Deny the Black on himself, not even to receive the shield.
While Construction Champion cannot knock down more than one enemy champion, it will not stop upon hitting the target. Using it while just behind a fleeing enemy allowing you to knock them down and then blink in front of then, making it harder for them to escape Shackles.
Both the armor from Emerald Light and Shackles are centered around the lantern, not Arcane Green Lantern. Since Emerald Lantern has a longer range than the armor buff, you will lose it if you toss it out to max range. You cannot reactivate the skill to retrieve the lantern, or by walking too far away, unlike Star Sapphire's Predator.
Retrieving the lantern can sometimes be counterproductive. It shortens the cooldown by 3 seconds, but the lantern completely leaves the match for the rest of the cooldown, removing the armor buff and preventing you from using Shackles. However, if Shackles is already attached to the lantern on the ground, retrieving it will cause Shackles to emanate from Arcane Green Lantern for the remaining duration instead.
Shackles can only be used on enemy champions, and only lights up when enemy champions are sufficiently near the lantern. It also does no damage.
Emerald Lantern, if not retrieved, always stays on the ground for the same time as the skill's cooldown, even if you acquire cooldown reduction.
Arcane Green Lantern will visibly be seen not carrying the lantern when Emerald Lantern is on cooldown, which is rare.
Deny the Black's huge range (6000, same as Regen Pad's deploy range) allow Arcane Green Lantern to assist faraway allies.