Roman might have left out the context, being Da Vinci nearly leaving because of the Demi Servants experiments, but choosing to stay for his sake. And the years she invested in winning his trust. "That's..." Roman wants to complain a little, but he admitted earlier she eased his burdens. The technical help is priceless, after all. "Truth. I can't deny she's essential for Chaldea to function as well as it does." Especially when most of their tech staff traveled with Marie to London. Then he snorts when Waver mentions his beloved Mari. "If was for Leonardo, she'll forbid it. She always gets on my case about it," he grumbles as if his hobby hurt anyone.

Silence lingers. London is a hot topic for many reasons, one he'll rather avoid thinking about until they restore the timeline somehow. There are priorities to have even against the heart wishes. After the awkward moment passes, he's glad to see Waver talking about his past in such light voice.

"Oh, why couldn't you-" He makes a hand gesture. Buy him a copy? "Did you have to return it?" He's curious because Solomon has been in his best behavior. Command spells didn't work with the King of Magic, but there's no need for them when he'll obey any command. He didn't have much of agency back then, but it's always curious how unruly other Servants could be.