Terlen

About the size of a grown man, a terlen has a flat, sharklike body, a long strong tail, and greatly extended pectoral fins stretched with translucent gray membranes that let it fly. It can fold these wing-fins back and slither like a snake on land, though it prefers swimming or gliding. Its huge mouth holds three rows of razor-edged cartilage. Normally a drab sand-gray, it can recolor its hide to blend with any background. It is amphibious and equally at home in water or out of it.

Perpetually ravenous, a terlen treats anything it meets as potential food. Each day they range over vast distances, skimming silently just over the terrain and using terrain and plants as cover, nearly as quiet as an owl. They usually approach from behind, giving victims -2 on surprise unless they are carefully watching behind them.

A terlen bites for 2d8 and fights with hit-and-run attacks, circling 30 to 40 yards away and darting in. It is happy to bleed prey slowly and let it exhaust itself trying to escape, sometimes pretending to leave and returning 10 or 15 minutes later for another ambush. Once its prey drops, the terlen sets down and crawls over to eat. It hunts water prey the same way.

Thanks to its camouflage, a motionless terlen has a 75% chance to go unseen, 50% in flight through smoke, haze or darkness, and 25% when moving in good light. Once it attacks it is spotted and stays tracked unless it leaves and comes back.

Small bands, known as flights or schools, are the norm. They do not hunt together, but when one finds food, others quickly arrive to steal a share. Packs of up to 40 have been reported, and being near that many during a feeding frenzy is madness. Very hungry terlens sometimes fight to the death over prey; there is a 5% chance per terlen present that between a quarter and half of them open the encounter fighting each other instead of attacking. Without lairs, they keep moving and seldom linger anywhere. They prefer water when it is available but can survive indefinitely in dry places, which let them spread from the wetter layers of the prison plane into the gray wasteland of despair and other harsher lower planes.

Terlens show that even the lower planes, often imagined as lifeless wastes of burning rock, desert and poison swamp, support tough food chains of natural and supernatural creatures, though usually twisted by the planes or the fiends who live there. Most likely the species began in the oceans of a prime world, its original shark- or snake-like form now forgotten. Perhaps a wizard or archfiend imported a few as curiosities or pets, which turned out hardy enough to survive the acidic waters of two of the prison plane's layers. The planes themselves may have changed them, or perhaps a scholar fiend or fiend of the prison plane bred them, but the result is a mostly natural predator tough enough for the lower planes.

They mostly eat ordinary hardy fish, birds, reptiles and small mammals, yet they now dare to prey on petitioners, larvae and lesser fiends found alone or in desolate places. In parts of the prison plane they have become dangerous enough for its native fiends to organize hunts. Terlens mate once a year, burying clutches of 50 to 100 eggs in pits of mud or sand and leaving immediately, so many hatchlings fall to predators. Young mature within a year and may survive 30 years, though most die sooner from their violent world or from trying to eat a greater fiend.