These shape-shifting rules apply to both voluntary and involuntary shape-shifting. The only
difference is the trigger. In case of involuntary (like that of a Werewolf at full moon)
the Character can try to resist the shape-shift but if they fail then these shape-changing
rules apply.
Sisu is a Finnish concept described as stoic determination, tenacity of purpose, grit,
bravery, resilience,[1][2] and hardiness[3][4] and is held by Finns themselves to express
their national character. It is generally considered not to have a literal equivalent in
English.
Sisu is a bit different from the other regular attributes. It measures how well the
character can overcome obstacles and persevere in the face of hardship. It also measures
how well the character can handle mental strain and recovery of said strain. The less Sisu
he has the more meek he becomes and will be more likely to crumble beneath the strain that
is life.