Hemlock
Hemlock is a sword with the power to possess people. Stip, a desperate young thief, starving and scrounging the dead bodies of some fallen adventurers for treasure, found this sword and was transformed by its power into a ranger, and a powerful crusader for good. Stip and Hemlock have been together for so long that the current entity is a kind of gestalt, and Hemlock’s consciousness is a mixture of a guttersnipe and an ancient weapon. This can be difficult for other people to deal with, and Hemlock has no real friends. But who needs friends when you can smite evil?
To some small extent, Stip’s and Hemlock’s motives can be separated. Hemlock lives on even if Stip dies, and its power will possess many more in the cause of good. Stip, of course, cannot take the long view like that. Nevertheless, Hemlock in a very real sense saved Stip’s life, and Stip, even without the power of the sword controlling her, would not give up the sword for anything. And Hemlock, even if it has at times over the years come across a host that may have proved even more suitable than Stip, is loyal to its current host and will do anything within the dictates of its alignment to save her.
Hemlock’s antediluvian, metallic xiphoid consciousness (which is, after all, what’s in charge) has a hard time understanding the rest of the party, or, in fact, anything beyond good and evil as abstractions. It knows perfectly well that Fearless Earless and Dark Deedman are not to be trusted, but as long as their malice is kept in check, or employed for good (nothing wrong with Dark Deedman assassinating orcs, for example), their presence is tolerated. Everyone else, except for perhaps Chance Datsun, who is a little suspect, Hemlock would gladly fight to the death for. Hemlock is not suicidal or stupid, and is, after all, obliged to preserve the life of its host, but is not afraid to die (whether this means the death of Stip or the actual sundering of the sword) for her companions or for the cause of good.
If Hemlock can be said to have any member of the party she is especially close to (which frankly she cannot), it would tend to be KL, who is also in possession of an ancient magical device, followed perhaps by Emil, who knows a lot of ancient lore, and Sliver, who is also a fish out of water among all these humanoids.