Neither he or Anders are the only Anders in the tower, but this Anders is the only one he allows himself to truly share anything with. Sharing secrets, sharing memories, sharing feelings, a language and sometimes a bed. He is not the only one he has slept with, but he is the only one that he has held in his arms afterwards, the only one whose hair he carefully detangles after having tousled it during their trysts. Neither is he the only one Karl takes delight in kissing, but he is the one he takes the most delight in kissing as their shared kisses are about more than the simple meeting of lips. He does not plan on telling him that any time soon, though – he would only let it go to his head, perhaps believing it to be due to his ability and not something else.
That something else is something dangerous, and best not spoken out loud. It is best to have it stay a secret, and not the kind you share, hidden under covers or in storage rooms or anywhere else. Not within the walls of the tower, at least.
The way Anders smiles at him like he does now, when they have a rare moment alone together, has him believing that he somehow knows anyhow.