A "T chart" is going to allow you to do a side by side comparison between two characters. I can't do a T chart easily via the Enotes system. Instead, I will break down two characters in two brief paragraphs.
Beowulf: He is the hero of the story. Think of Captain America, and that's basically Beowulf. He's a manly man. Beowulf is strong and brave. He's universally loved by just about everybody. He's a natural leader, and he would put his own life in danger rather than risk the life of his men. He's also a humble man than enjoys doing his heroic deeds for the sake of the deeds, not the money.
Grendel: He is the bad guy of the story. It's not clear if he is a man or monster. He/it is described as a man eating demon that has descended from the Biblical line of Cain. He enjoys violence for the sake of violence, and he uses it to terrorize soldiers and innocents alike. He is strong like Beowulf, which explains why no normal warrior has been able to defeat Grendel.