Terra, Magical Adept // Esper Terra

Cards

Cast
Spark Double by paying ({3} magic symbol) ({U} magic symbol) , choosing to have it enter the battlefield as a copy of
Esper Terra that isn't legendary. This will cause it to enter the battlefield with a lore counter as it will be a Saga.
Spark Double's first chapter ability triggers, creating a token copy of
Spark Double with haste, which will enter as a copy of
Esper Terra with haste that isn't legendary and with one to four lore counters on it.
The
Spark Double token's chapter abilities will trigger according to how many lore counters were placed on it.
Resolve the first
Spark Double trigger, creating a token copy of
Spark Double with haste, which will enter as a copy of
Esper Terra with haste that isn't legendary and with one to four lore counters on it.
Repeat from step 3.

This combo has been estimated to be Ruthless (Bracket 4+).