Whoa... hold up a sec: Be careful with reading guides, things change over time, thunder not being good at endurance is a thing of the past. Dian is here now, and there's a reason ppl call her the absolute BEST HEALER in the game, and we just got the dual HP weapons for thunder as well (although, granted, not the best) so a thunder grid isn't completely missing out on HP anymore. A team of Raiko/Marduk/Dian is insanely durable, the fourth is just w/e you need, although typically will be Nuwa (coming in a few months).