There are strange circumstances where people may take on peculiar colours. The blue Fugates are a famous example, then there are conditions that give skin a green pallor, jaundice can make people look shockingly yellow. In an exercise in 'what if...' I present those phenomena filtered through a fantasy physics lens and give you the tyndall, the next in the series of weird extra-planar humanoids for your entertainment.
Tyndall
by Cab Davidson
Stat Tyndall AC: 8 HD: 1* Move: 120’(40’) Attacks: 1 weapon or special Damage: By weapon or special Number Appearing: 2d4 (10d6) Save As: F1 Morale: 8 Treasure Type: E Intelligence: 11 Alignment: Lawful XP Value: 11 Tyndall are among the most human like of outer-plane humanoid races, being of similar size and build, but of more striking skin colour, from red through to violet, essentially anywhere on the spectral range, but without the complex mix of tones of humanity. In daylight, other than their peculiar and vivid colours they appear as humans. In the dark, however, they can be observed to dimly glow that colour. Their strange colours do not seem to be inherited, with siblings often having little resemblance to each other or to their parents.
They are found on several of the outer planes of energy, where they thrive, being placed there by various immortals to colonise and for specific tasks. They can also live successfully on the prime. They are generally peaceful, being content to harvest energy from light sources where they live. They absorb every wavelength of light that hits them except for one, being the colour they both reflect and (slightly) radiate.
They can choose to fight with weapons or by using the light energy that is so essential to their beings, and it can be used in many different ways. In any round, they may choose to radiate an intense flash of their own colour, partially blinding all foes using visible light to see to their specific colour (no saving throw) conferring a -6 to hit rolls against them for 6 turns. They may also, once per turn, emit a monochromatic beam of light from their eyes to a single target within 180’, inflicting 2d6hp damage (save vs. wands for half). A group of 4 tyndalls can coordinate flashes of colour such that enemies struggle to focus on a single creature, giving each tyndall +2 to hit in combat.
Tyndalls are, for energy creatures, surpisingly calm and slow to anger, and they are unlikely to initiate combat, preferring discussion. Advenurers are known among them, and they favour magic user and mechant classes.