Sunlight damage
For Gloom, bright sunlight is not merely unpleasant but life-threatening.
Gloom avoid bright, dry daylight before it begins to burn them. Autonomous routes favour shade or a return to a reachable nest. If a Gloom crosses the damage threshold, it steadily loses health and immediately seeks shelter. This is environmental harm, not an enemy's blow, so ordinary group defence does not soften it.
Rain offers borrowed shade
Rain dims the light that actually reaches the ground and can prevent damage for a time. For route choice, however, what matters is how bright the place would be without this passing shelter. A Gloom does not carelessly linger at a boundary darkened only by rain: when the shower ends, the same route can become dangerous at once.
Caution and direct control
At dawn, autonomous Gloom seek shelter early if they know a reachable dark place. Direct player control can override this caution, but not the effect of light itself. No sunlight reaches them below ground; moving sources such as active Aqua present a separate danger there.
Rain still covered the clearing, yet the Gloom waited in the first trees' shade. Soon afterwards, the cloud cover broke.
