Absorption and evolution

Absorption is the main way a Slotbound army gets stronger. The official store text is blunt: weaker units are sacrificed to feed the strong, and “branching class choices” change the run. This page stays with mechanics. Named promotion targets live on units and evolution.

What official sources confirm

You absorb one unit into another. The Steam achievement Become One is awarded the first time you do it.
Units have an Absorb LV. Bloated Beast is awarded for raising one unit’s Absorb LV to 100.
There are 6 families. Devourer of All is awarded if one unit absorbs units of all six. The official family list is [verify in-game] (the demo launch post names Warriors, Archers, Mages, “and other units”).
Units have a star rating. Achievements exist for raising one unit to 3 stars, and for winning a battle with 5 or more 3-star units deployed.
Promotion is a real, separate step from raw feeding. Official v1.0.0 (4) fixed “the next Class Select not opening right away after a promotion” and Fate Stone quests that grant promotions. Official v1.0.0 (5) fixed stat arrows displaying incorrectly on Class Promotion cards, and fixed some unit skills not triggering or missing against certain enemies.
Official demo v0.3.0 added a manual lock that prevents selected units from being used as absorption materials, and an Absorb Mode toggle (A key).

How players describe the action (verify in 1.0)

A widely quoted Steam discussion from the demo period (July 2026) describes this procedure. Confirm it in the current build before you treat it as a tutorial:

Turn Absorb Mode on (A key, and/or a cloak icon whose eyes glow when absorb is armed — [verify in-game]).
Drag a source unit onto a target unit.
A prompt appears. Players said you then choose whether to give the target the source unit’s skill, or to take a stronger absorb that contributes more to leveling / class progress. You can cancel if you grabbed the wrong pair.
With Absorb Mode off, the same drag only repositions units.

That “skill versus more absorb XP” choice is [verify in-game] for 1.0. Do not assume every patch still offers the same two buttons.

Players also reported that you can sometimes start a wave with extra unabsorbed units still on the field, past the usual cap, and that hidden units sitting behind others can make the board look emptier than it is.

Practical rules that usually hold

These are play patterns, not patched patch notes:

Feed one or two carries, not the entire roster, before the first Judgment.
Lock anything you cannot afford to lose, including a rare roll or a unit mid-promotion.
Inspect before you drop. Imprints and Random Stats are why two Warriors from the same spin are not equal. Route the better modifiers onto the unit you plan to keep.
Class-matched fodder is the safe default for promotion progress. Whether cross-family absorbs are weaker, equal, or required for certain bonuses (the “all 6 families” achievement implies they are at least possible) is [verify in-game].
Stars and promotion are different axes. Official achievements treat 2-star and 3-star ranks as raise-able goals, and they also treat “Normal-grade” as a category you can deliberately stay in (see Pride of the Commons and Ordinary Is Special on the achievements page). A 3-star base unit is not automatically a capstone class.

Absorb LV, stars, and awakening

Absorb LV is an official numeric track on a unit. What it grants per point — raw stats, skill ranks, or promotion eligibility — is [verify in-game].

Awakening was added in official v0.4.0. Public demo guides often describe awakening cards at unit levels 30 / 60 / 100. We have not seen those numbers in an official news post, so they remain [verify in-game].

Common failure cases (including patched bugs)

Wasteland Camel: official v1.0.0 (5) fixed a bug where dropping a unit onto a camel that already had a rider swapped them. If you are on an older build, update.
Promotion UI: if Class Select or Fate Stone promotion goals seem stuck, make sure you are on v1.0.0 (4) or later.
Irreversible clicks. Locks exist because a mis-drag can delete the wrong unit. Pause, lock, then absorb.
Demo guides that stop at two capstones. 1.0 discussions name many more promoted units than the old “Warrior → Paladin → Veil” summaries. Use the in-game Collection.

Related pages: units, imprints, how to play.