Unit Evolution

Unit Evolution, or Senioring a unit, improves a units in a few ways:
 * Increases base stats (HP, Attack Power and Defense) by 50-100%.
 * Increases the Star Level of the unit (Normally by 1, sometimes by 2).
 * Increases the passive buffs earned from various Medal Level milestones.
 * Allows the unit to Transcend.

Cost
Evolution cost is determined by the new Star Level the unit will reach: