Player Companion

A player companion helps the player through the whole game. Take these npc's for example npc_alyx, npc_barney. You know how long they've been in the game and how many people they take out, they're built to have more health than allies like the npc_rebel. They are mostly scripted with max or regenerating health, so they can protect and live longer defined by their ai or sequences or even the type of person. Allies are a rough good help with tactics able to take down a army. Barney is a disguised kind of guy who is neat and uses many weapons unlike Alyx with the shotgun and alyxgun also known as the Super Pistol. Companions will have a longer lifetime. CS:S Bots are companions, they have a lot of health, and can take down a player real easy.