Issei and Rias have a chat! And they make a discovery about Issei's power!

Back at the club, Issei was getting settled into a couch with Rias in his lap. "So, how did it go?" she asked him as she cuddled into him.

"I think I laid some decent ground work," Issei noted. "She's definitely considering becoming a Devil now. And I think I erased some of her indoctrinated beliefs about sex."

"Good. I suppose you're going to try to ease her into it?" Rias inquired.

"A little, though I admit, it might be a bit hard to wait on that," Issei shrugged.

Rias nodded, before adding, "At any rate, we need to talk about something else. Get your Sacred Gear out."

"...okay?" Issei replied, doing exactly that, the gauntlet materializing. "What now?"

"Try using your boost ability, then again as soon as possible," Rias told him after taking a moment to examine it. "I think it's more powerful than we initially thought."

Issei blinked, and boosted. Then, after focusing, he realized he could do it again after ten seconds. "What the?" he asked, stunned. Rias beamed.

"Well, that certainly explains why it took all of my pawn pieces to revive you. More powerful individuals require more point values in order to ressurect, and you can use multiple of the same piece. Unfortunately, pawns were the only ones I had multiples of, since I gave a piece of everything else out already," Rias explained. "We initially thought your Sacred Gear was just one that doubled your power, and that was it. Not too bad, but not anything special, either... but that Gear... while your strength will reset after each fight, during said battles, you'll be able to grow exponentially stronger. Doubling your power every ten seconds is not something to trifle with. In a long enough fight... you would even have the ability to kill a God."

Issei stared at the gauntlet, speechless. "Whoa... that's incredible..."

"It is... though naturally, you being a pawn poses a problem. We already discussed that you're the piece most likely to be targeted first, and given your Gear needs time to really get going..." Rias sighed. Issei groaned. When put like that, pawn really was the worst piece he could be. "...no helping it then, especially since you're already going to have Fallen Angels after you," Rias grinned, standing up. "It's time for some intensive training that's going to make Akeno veeeerry happy~! We're going to drill an essential skill into you that will keep you in play as long as possible!"

"...what skill is that?" Issei paled, knowing that anything that made a sadist happy would be something no doubt very unpleasant for him...

(Side note, it has been a while since I had read the manga, and I didn't get far before life made me too busy to continue at that time, so I am kind of reading it as I go with this branch. As such, I completely forgot that Rias used all eight pawn pieces on Issei, and thought Asia was made a pawn on her revival. I have edited the chapter where she offered the pawn piece. Also, anyone who can predict the next chapter title due to being able to see where it is going will get a whole batch of cookies! Because it's going to be one big reference!)