Ayumu: Huh?! Gee, I didn't know I had a sister!

This pleases me for some reason.

Oh wow, when I posted this I looked up the ship just to see that it existed. I figured Morichan simply picked the one ship that would crossover with his favorite character of choice despite being way too old for Kantai Collection. It was launched in 1902 and used for the Russo-Japanese war.

In actually though the Kasuga survived to and was even still being used by the IJN during WWII (even if it was only a disarmed barracks ship at that point) and wasn't sunk by the Allies until two months before the end of the war in 1945. Serving for 43 years without fully being taken out of service isn't a bad run for a warship.

EDIT: Digging into this further, there was another super long-serving armored cruiser from roughly the Kasuga's era, the Yakumo. It was launched 3 years earlier in 1899, survived to WWII, was still actively used in the war as a cruiser (rather than being stripped down and reclassified like Kasuga). It survived the war without getting sunk, and continued to be actively used after the war was lost as a transport for the better part of a year to bring people back to Japan from it's previous holdings before finally getting scraped in 1946. That's an even better run of 47 years. Kantai Collection and the other WWII naval gacha games should implement her.