力線の暴君

25/09/20

Once Leyline Tyrant leaves the battlefield, you have until the end of the current step or phase to spend whatever red mana is in your mana pool before it empties as normal. There is no penalty associated with this other than the loss of the mana.

25/09/20

You can keep red mana in your mana pool indefinitely while Leyline Tyrant is on the battlefield. That means if you add a red mana to your mana pool during one step or phase, you can spend it during a later step or phase, or even a later turn. Other types of mana will continue to empty from your mana pool as each step and phase ends.