Strain

See also: Attunement, Bloodstones

On Tessera, many casters understand magic as interacting with the Weave. See PHB 205 for an introduction to the Weave. However, on Tessera using magic comes at a cost. For both arcane magic and divine magic, interacting with the Weave can lead to side effects on the caster, called Strain Effects.

Check for a Strain Effect after a long rest, just before recovering spell slots. As part of this check, you don't include any slots created by Sorcery Points, Arcane Recovery, and the like.

The chance of a Strain Effect is based on the highest level slot used the previous day: (1+Level)%.

The severity of the Strain Effect is usually proportional to the total levels of slots used the previous day. The DM chooses the severity and the effect, based on these guidelines:

 Total Levels of Slots: Strain Effect
 1-9: Mild
 10-18: Moderate
 19-27: Severe
 28+: 2 or more Effects

After checking for a Strain Effect and resolving any effect, continue with recovering spell slots as normal.

The most common Strain Effects are mental. Mild effects can include reduced impulse control, a compulsion, an obsession, or a phobia. Moderate effects can include paranoia, addiction, or depression. Severe effects can include a psychosis--a complete break between the mind and reality.

Physical Strain Effects are rarer. Mild effects can include changes to the caster's eyes, hair, skin, voice, etc. Moderate effects can include a severe allergy (e.g., to sunlight), infertility, or a metabolic need to ingest gold. Severe effects can include substantial and possibly grotesque distortions (e.g., shorter or longer limbs), additions (e.g., a second mouth), etc.

The nature and magnitude of Strain Effects are related to the nature and magnitude of the magic. For example, a caster who gains a strain effect from casting fear spells might develop a phobia.

Strain Effects are rarely advantageous. Of course, a caster already suffering from mental effects might view a new physical effect as an improvement. Once developed, a Strain Effect is a permanent, non-magical phenomenon. For example, Remove Curse won't remove a Strain Effect. Depending on the nature of the effect, mundane or magical means might temper or remove it (e.g., counseling, surgery) (DM's choice).