When I was a kid, my dad bought me a CD with only Pain arc on it. And everytime I watch it, I always replay for like 56 times the intro song lmao. Tourmei Datta Sekai >>> Silhouette
the first cd i owned was of itachi vs sasuke, jiraya vs nagato arc only, and my friend had the pain in konoha attack arc which i really wanted to see but could not really so yeah watched this arc over and over in childhood - brings back the old memories. The jiraya training nagato, in rain- the itachi sasuke fight. the opening is really good too