I'm designing mechanics for a Naruto campaign using Savage Worlds, and was thinking about how characters improve in media and in RPG's. In RPG's characters usually earn XP each session or each encounter and advance between sessions. Some have this presented as lengthy downtime spent training between sessions, such as in Dark Heresy. Others simply have advancement happen between sessions, but the XP is only representative of what they learned in the session.
I've never seen a tabletop rpg in which heroes are "made". A lot of media depict characters who improve in skill when they are placed in dramatic situations, their skill rising to meet the challenges they're faced with. In reality, both lengthy practice and rapid advancement due to challenge are true, and Naruto depicts this as well. I'd like to have a way to show that in game.
What I'm hoping to get out of this is the classic scene of a character whipping out a new skill or improved abilities to take down an opponent that they couldn't defeat before the fight started. Whether it's a character putting in new contact lenses and breaking out a literal death glare, or a character deciding that it's "now or never" on a new technique they'd never been able to pull off before.
Heroes being forged in the fires of battle is the cause of so many Crowning Moments of Awesome in media, and I think that having that represented in an RPG would add a lot to the experience.
What I've been considering is essentially allowing players to pre-purchase advancements during dramatic fights, with the idea being that they can use them to improve and overcome the challenge but must spend their next advance on that improvement. This could work as is, but I think it needs a bit more to it before it really fits the bill.
There are a few things that I'm worried about regarding pre-purchased advancements mid-fight. The first is that if the players have an option to level up now, but earn xp later, the system would incentivise doing so every single time. In fact, it would almost feel like a punishment if the player didn't pre-purchase every time, as otherwise it would take up to double the usual advancement time to reach a new level. They'd wait the duration of their pre-purchased advance, then an entire new advance to improve again.
The second is that the advance might not actually be worth enough on it's own to allow the dramatic scene of an underdog rising to defeat their superior opponent. I'm not entirely sure how well Savage Worlds works for one on one combat. I've found that a vastly overpowered individual is still no match for groups, though I think I've hit on a way to allow for individuals to be more powerful than groups by altering the action economy.