Call it a lack of other meaningful symbols to use that wouldn't also embarrass him to be seen with.

He sniffs and settles back into position. But his gaze does end up skirting over Rhea'li as well, noting the marks on their own skin. Why... Why is there a Ruin geometry inked on your thigh, Warrior? Emet-Selch makes a pained face at the sight.

"No. I suppose the memory of it was strong enough that the image imprinted itself upon my skin." He shifts a little. "This body isn't quite flesh and blood, you know. It's an excellent facsimile of one."