Ettercaps are arachnid-humanoid hybrids, and not the adorkable, crime-fighting type. They live in forests, herd spiders, and generally lend an air of gloom and despair to wherever they live. Anytime a party of adventurers encounters an ettercap, it will be accompanied by at least a few giant spiders.
Ettercaps are robust in all their physical abilities, with Dexterity leading by a nose. They’re not afraid of a toe-to-toe confrontation, but considering their high Dexterity, combined with their Stealth and Survival skills, an ambush scenario is more likely, perhaps with the ettercaps beginning the encounter hiding in trees (thanks to their Spider Climb skill). They also have darkvision, Web Sense and Web Walker, making it advantageous for them to blanket dimly lit parts of thick forests with webs and wait for hapless travelers to get stuck in them. Alternatively, if there’s a road or trail that passes through their forest, they may lay webs across the path which even travelers who notice them and aren’t caught in them will still be stopped by, giving the ettercaps an opportunity to attack. An adventuring party that makes camp in the woods may wake in the morning to find its campsite entirely encircled by webs.
Ettercaps initiate combat from hiding, whenever possible, and try to gain the element of surprise. If a player character is restrained within one of their webs, they attack that PC first; if one of their spiders is moderately injured (reduced to 18 hp or fewer), the nearest ettercap focuses on whichever PC did the damage. Otherwise, they choose their targets indiscriminately.
Against a restrained target, an ettercap uses its Multiattack action to claw, then bite. Against an unrestrained target, it uses Web to try to restrain him or her. Web has a recharge, so if this action isn’t available, an ettercap without a restrained target will Multiattack any opponent who’s engaged it in melee, or an opponent who’s poisoned by an ettercap or spider bite (it can tell). If it has no obvious target, or it’s being attacked from range or by more than one opponent, it may choose the Dodge action instead, marking time until it can use its Web again and thereby gain an advantage. That being said, since ettercaps will invariably have giant spiders fighting alongside them, and the spiders also have the ability to ensnare their targets in webs and poison them, there should be no shortage of debilitated targets to choose from.
Ettercaps aren’t that smart, but neither are they lacking in survival instinct. If they’re seriously injured (reduced to 17 hp or fewer), they’ll back off (using the Disengage action, then their full movement speed), and they’ll take their spiders with them.