Mark of Morte'ryuu

You have entered the Void Realm and met what lies inside. The Voidborne beast has left her mark on you, opening your mind to ancient eldritch knowledge. You learn a new way of twisting your spells to your will, to your demand. Upon taking this feat, you learn the Maximized Metamagic option. 

Metamagic: Maximized - When you roll damage for a spell, you can spend 5 sorcery points instead to have the spell deal the maximum amount of damage.

• You can use only one Metamagic option on a spell when you cast it, unless the option says otherwise.

• You gain 5 sorcery points to spend on Metamagic (these points are added to any sorcery points you have from another source but can be used only on Metamagic). You regain all spent sorcery points when you finish a long rest.