Goddesses of Luck. By the way, why did her luck got boosted at Kai Ni? Nishimura fleet's survivor's reference?
She gets a lot of credit for that, but it's really not that lucky, since she was badly damaged, and really only survived for not being a bigger, juicier target, or trying to rescue survivors like her fellow DDs that sank did. She was also sole survivor of several different conflicts, however, making her similar to Yukikaze... except Yukikaze lasted the whole war, while Shigure sank a little while after Leyte.
(Meanwhile, Shoukaku is "UNlucky" because she survived taking damage fairly often...)
Nor did she have a spectacular war record to support all the bonuses to her firepower she gets. (In the Nishimura fleet/Leyte, she didn't even get within RANGE of the main enemy before being forced to retreat.) She was at Guadalcanal, and rescued Hiei survivors, but didn't take part in the battle. In The Battle of Vella Gulf, she was the sole survivor of four destroyers in a sneak attack (like Hiryuu, being the lucky one not sunk in the first salvo), and retreated without damaging a single American ship. She only contributed to damaging USS Selfridge (DD), and maybe sank USS Growler (SS).