You can't evolve generals to five stars. An EVO emblem can only be applied to a three star general in the process of evolving it to four stars. In particular, if the general is already four stars, you can't apply the EVO emblem. And yes, it's +5 to power, leadership, and intelligence.
The third map of the daimyo world boss drops "Sword of Light and Shadow", which increases damage to your primary target by power x10, or power x15 if "the target's DEF is higher than hers." It's a high level weapon, and with higher per-level attack bonuses than most weapons offer. But the effect on it is pretty much junk, as that's only going to be about 2k damage to one target. To the vendor it goes.