Titanium/Diamond Shield should say "by 1" rather than "to 1" as Diamond Shield should only be reduced to DR2
Besides immaterial shields, this seems least effective against Bone Wall, which is good since a strength of Bone Wall is PC resillience. If you wanted to be harsh you'd halve the stacks. What happens if you use Corrodation twice on Bone Wall?
On Dim Shield: Can this destroy it? May be better if it sets counter to 0
Should be renamed to Corrosion | Corrosion