L (Flex)

Strategy and Synergy
Much like it will consume the spell upon cast. Flex however is more defensive, being useful in expanding the of the player on cast. This makes Flex useful for low-cost spells that can be easily expended without much of a hassle such as.

This upgrade is particularly useful when playing as Solo Saffron or Bullethell Gunner since those two starting kits generally begin with very low maximum health.