Fervent Thopterist

Whenever you cast your first artifact spell each
turn, put a forge counter on Fervent Thopterist.
Whenever Fervent Thopterist attacks, create X
1/1 colorless Thopter artifact creature tokens
with flying that are tapped and attacking, where
X is the number of forge counters on Fervent
Thopterist. Exile those tokens at the beginning
of the next end step.