Damage and status effects are two completely separate phenomena in the rules of Spiral Knights. Read the wiki pages "Damage" and "Status effect" to get them sorted out. For example, in weapons we have Dread Venom Striker (normal and poison), Plague Needle (piercing and poison), Venom Veiler (elemental and poison), and Biohazard (shadow and poison). See how poison has nothing to do with the damage type?

New players sometimes confuse them because they often arrive together. For example, suppose that you walk onto a fire grate that starts spewing fire. The fire grate does elemental damage and induces the fire status. While you are on fire, you periodically take damage, which appears to be normal damage (from its color) but which is not lessened by any kind of armor except fire armor. For another example, suppose that a shock greaver attacks you. You suffer shadow damage and receive the shock status. While you are shocked, you periodically spasm and receive elemental damage.

I believe that fire zombies' breath in FSC is pure fire status, with no damage whatsoever. So the wiki is oversimplifying there (meaning, leaving out some cases), I think.

If you want to know what a monster deals, then look up that specific monster on the wiki. For example, the trojan butt-bump inflicts shock and, apparently, normal and shadow.