Dyoooooooon

Just came back after taking a break after spending my stash during Walpurgis. How do I use the magical Don? She's seems like a weird unit. If she's positive SP she does rupture and if negative Sinking? How do I even keep her negative, if I go for sinking?

Also does T-Corp Outis replace Molar for Tremor? I must admit that all these hybrid units released recently seems a bit annoying to me, I would rather just that they kept to one status