With absorption any time you use a basic ability, it will permanently add +3 maximum energy and and +0.0195 energy restoration to your hero. This effect will stack up to 100 times. After absorption has been fully stacked, you gain +300 maximum energy and +1.95 energy regeneration.
All heroes that require Absorption also require the Compartmentalization Perk or the Lightweight Mastery to be used effectively.
Note: The definition of a basic ability is an ability that does not require a Mastery to use. For example, Predator's blink ability is NOT a basic ability because it is only available if we pick the Blink Mastery.