Mordekaiser

Arena changes

• R: If Mordekaiser kills his target, he will keep any stolen stats for the remainder of the round.
• R: If Mordekaiser is in the Death Realm with the target dummy on the shop platform map when the combat phase ensues, he is immediately forced out of the Death Realm, ending the ability prematurely.
• R: The Ring of Fire is special-cased to not apply its effects against units inside the Death Realm.
• R: In the Reckoner Arena battlefield, the pillars will stay visible and will behave as normal inside of Death Realm, with the exception of them being untargetable.
• R: Twilight Shroud will follow her between realms.
• R: This bug was fixed on patch V14.1, but it is still present in Arena.
• R: If someone who enters the Death Realm has the augment Chauffeur, their hitbox will follow their ally, while they appear to stand still at the position where they entered the Death Realm.
• R: Only when they cast an ability, will they visually teleport to their real position. Once the cast of that ability is over, they will visually teleport back to their original position.
• R: If the ally of someone who enters the Death Realm has the augment Chauffeur, this ally will follow them into the Death Realm.
• R: This ally will only follow the main target out of the Death Realm if they are currently attached or once they reattach.
• R: That means that if they have a way to permanently deattach from their ally, they can permanently stay in the Death Realm.²

• A healing-focused build uses Protein Shake and Radiant Virtue in its first two rounds, followed by Moonstone and Spirit Visage; Moonstone and Spirit Visage increase Mordekaiser's W shield and the heal from its recast.³
• A healing build with Protein Shake can counter teams relying on Shardblade, since healing or shielding can counter Shardblade users who cannot buy anti-heal.⁴
• Mordekaiser can deal a lot of damage with a shield-focused build.⁵

Realm of Death slows the target champion, then banishes them with Mordekaiser to the Death Realm for a few seconds, cancelling interactions with units outside it.⁶ Patch unknown

Realm of Death heals Mordekaiser for a portion of the target's maximum health and temporarily steals a portion of their attack damage, ability power, attack speed, maximum health, armor, magic resistance, and size.⁷ Patch unknown

• In the Reckoner Arena battlefield, pillars remain visible and behave normally inside the Death Realm, but cannot be targeted.²⁸ Patch unknown
• When Realm of Death is used on a champion whose ally has Chauffeur, that ally follows them into the Death Realm and follows them back out only while attached or after reattaching. A way to detach permanently can leave the ally in the Death Realm.²⁹ Patch unknown
• With Chauffeur and Mordekaiser's Guest of Honor effect, the interaction can result in a 2v1 or leave a player unable to move in the Death Realm.¹⁰
• Ethereal Weapons with Moonflair Spellblade can make Mordekaiser's passive ticks reduce its cooldowns very quickly.¹¹

• Akali's Twilight Shroud follows her between realms. This bug was fixed in patch V14.1 but remains present in Arena.² Patch unknown
• If Mordekaiser is in the Death Realm with the target dummy on the shop platform map when the combat phase starts, he is immediately forced out and Realm of Death ends prematurely.² Patch unknown
• If a champion with Chauffeur enters the Death Realm, their hitbox follows their ally while they appear to stand still at the position where they entered. They visually teleport to their real position while casting an ability, then teleport back after the cast ends.² Patch unknown
• With Chauffeur and Mordekaiser's Guest of Honor effect, an ally can become stuck in the regular realm and unable to move.¹²

Earlier formats

• In patch 26.5, Mordekaiser's Guest of Honor was fixed when it failed to work on some occasions.¹⁴ 8x2 duos
• In patch 25.19, Mordekaiser's Guest of Honor no longer conflicted with revives or persisted when a champion died.¹⁵ 8x2 duos
• In patch 14.18, Sylas no longer kept the stats stolen from Mordekaiser's R indefinitely.¹⁶ 8x2 duos
• In patch 14.11, Mordekaiser's R consumed Malzahar's passive shield when cast on him.¹⁷ 8x2 duos
• Zed's It's Killing Time can mark everyone in Mordekaiser's Death Realm, regardless of team or Arena.¹⁸ 8x2 duos
• A Chauffeur ally can remain stuck and invulnerable in the Death Realm for the rest of the round after one opponent is killed.¹⁹ 8x2 duos
• Killing Anivia with Realm of Death can cause her to disappear from the Death Realm while Mordekaiser remains there.²⁰ 8x2 duos
• A Mordekaiser with Chauffeur and a Mystic Punch Volibear ally could pull the opponent into the Death Realm with them, leaving their opponent's ally outside.²¹²² 8x2 duos
• Realm of Death could pull both players into the Death Realm when Mordekaiser had Chauffeur.²³²² 8x2 duos