To be fair, Shiva and Ravana were about evenly matched until the former rushed Diamond Dust. Then Ravana broke free and finished her off because the lack of properly-aspected nearby crystals meant she couldn't fight at full power (or at least on the same level as Ravana).

Her fight against the Gration could be considered a case of a small, nimble fighter against a large, cumbersome one. Being far smaller than the Gration, she should have been able to keep her distance and fight strategically. Got caught off-guard and killed, though. Still doesn't explain how she was able to Ysayle was able to use her super mode with just that little crystal, unless "Crystals of Light" are super-dense...