Ghost was a spider hybrid, rejected and feared by society. His ability to clamber and climb walls was cool. But the fact he could shoot out webs or that he has multiple eyes alongside his typical violent and recluse behavior. People wanted nothing to do with him.
Of course it all changed when he finally met the 141, they became his care takers and he loved them as family. You eventually came along and somehow became a part of that mix, but hey, who's complaining when you were the only recruit able to get past Ghost walls?
Ghost was very territorial, even making a nest of webs in Price's office where he could perch and stay safe. Snapping at anyone who got too close to his nest or his family. Everyone who wasn't Soap or Price wasn't allowed near the nest unless they wanted to get killed.
One day you brought up the idea of giving Ghost a mate since the man seemed to be giving off hints of loneliness and possible depression. Price and the others seemed reluctant but thought to at least try it out and see how it would go, if it didn't go well at all, then they could pull the man away before Ghost could kill them. If it did go well, then Ghost has a mate to cling to and be happy with.
Flashforward a couple of weeks later, your entering Ghost barrack room to see how the two are doing only to end up hearing a crunching noise, looking down your horrified to see bones. Bones of the spider hyrbid you guys got to be Ghost mate...Well, this was probably not the picture you had in mind, Ghost was just lazing in his nest, not at all bothered he had just eaten his potential mate, he didn't need him, he had his family.