It's tagged on pixiv as 東方五大老, the Touhou Council of Five Elders, with my dictionary pointing out that 五大老 usually refers to the "council of five elders formed by Toyotomi Hideyoshi to rule Japan until his son Hideyori came of age." I'm stunned there's not a tag for it here. Or if there is that no one's tagged this yet. I wouldn't know what it was called though.