The only sentient item in the current game is "First Blood", a sentient +2 eager keen rapier of quickness that offers a number of speed related quickened spell-like abilities. First Blood's motivation is do destroy any threats before they can do harm, so it likes to kill anything that threatens its welder as soon as it becomes obvious its a threat, it likes to attack first, and it likes to make sure whatever it is fighting is dead so it can't ever be a threat again. The more blood that "First Blood" drinks (that is, the more living things that it kills), the more powerful it becomes and the higher it's ego goes. It's mildly Chaotic Evil, with a tendency toward Chaotic Neutral in that it only kills the dangerous and violent, and never the meek and mild. At some point, if the PC doesn't get rid of it, it's going to end up nigh TPKing the party. The player that has it though just refuses to give up its sweet sweet power.
Unlike the comic you reference, all of the "great swords" in my game basically hate each other and can sense each. Which can get very "highlander" like if a great sword wielder meets another great sword wielder, especially if the great swords purpose is contrary to each other. Encounters between swords generally involve one sword demanding that the welder kill the welder of the other sword. In the case of first blood, that could very well mean immediately coup de grace the sleeping welder of the other sword.
The only other great sword that they've encountered so far is "Veil Cutter", which is a sword with the purpose of exposing lies and deceptions. It belongs to the elf scholar Edelhard, the Mayor of the Palace in Talernga, servant of the Hurin and Hinga, and effectively the Prime Minister of the government. Since "Veil Cutter" is LN and knows the nature of "First Blood", had the wielder of First Blood lied in his presence, things would have gotten really touch and go, with likely both sides needing to make ego checks to avoid killing each other right there in the throne room (which would have certainly gone badly for the PCs). Edelhard was however wise enough not to threaten the PC, and the PC wise enough not to try to lie to Edelhard.
"Wyrm Slayer", "Flametongue", "Frost Brand" and so forth are the names of intelligent swords in my game.