Rellana, Twin Moon Knightess

Protection from red.
When Rellana enters, detain each nonland permanent your opponents control with mana value
4 or less. (Until your next turn, those permanents
can't attack or block and their activated abilities
can't be activated.)

"Rellana renounced her noble origins as heir to the throne of Caria to follow Messmer in his crusade in
the Shadowlands, there she became his blade, his closest ally and friend"