Spend enough time beside another mutant on Krakoa and you start to change.

Plasticity is a relationship‑progression system. It represents the way repeated social contact with another mutant makes your character adapt to them: picking up habits, instincts, resistances, and eventually shared techniques that only exist because of the bond.

It deliberately separates what the relationship is from how strong the bond is. You name your own relationships: Friend, Rival, Mentor, Nemesis, Drinking Buddy, Crush; and the label carries no rules weight at all. The Relationship Level does. Plasticity is the biological metaphor at the heart of the system. Repeated interaction creates the capacity for adaptation: the more your character engages, the more they can be changed by the people around them. Your relationships don't just record who you know. They physically and behaviourally change who your character is.

You earn Plasticity by engaging with other players: making a First Impression, turning in your roleplay bounties with other characters, and submitting social scenes, all subject to a weekly cap.

Each bond has a Level from I to V.

There is a one‑level difference limit. Neither character can be more than one Level ahead of the other: if you are Level III with Wolverine, Wolverine can be Level II, III, or IV with you, but not I or V. This makes every Plasticity Bond inherently reciprocal without forcing the two characters to feel exactly the same way about one another.

1. IHabituation: Habituation is the decrease in response to a repeated, familiar stimulus. It is the biological manifestation of mutants becoming accustomed to each other's behavior and powers, their bodies begin making small adjustments simply because they spend so much time together.
   Benefits: Each mutant gains the ability to develop a Habituation Perks.
2. IIAdaptation: The bond has moved past habit. Your character has actively adapted. The benefits get stronger and more specialised, and the relationship can begin developing its first Symbiosis Technique: the start of the two of you being able to merge your powers to great results.
3. IIISynergy: Genuine mechanical synergy. Your abilities, instincts, or behaviours start producing effects neither character has alone: You gain access to Synergy Perks that activate whenever you are together.
4. IVIntegration: TBD
5. VSymbiosis: At this stage of Plasticity, the relationship has developed into a stable and specialized biological association. The cumulative adaptations of both mutants allow their powers to function in coordination. Symbiosis represents the mature expression of their relationship: two distinct individuals whose specialized adaptations allow them to function as an exceptionally cohesive whole.
   Benefits: The two mutants gain a shared Symbiosis Technique.

Every bond on Krakoa, drawn as a web. The thicker and darker the line, the deeper the bond both sides have developed; a dashed line is a bond neither side has developed yet. Click a character to see their bonds.

When you establish a Level I Plasticity Bond with a character you pick one of the three perks below, drawn from their Mutant Class. In play: +plasticity/bond <name> to establish the bond, then +plasticity/perk <name>=<perk> to choose.