Complex Rules & Layers Mastery

Within a layer, timestamp order applies unless one effect is dependent on another. Effect A depends on effect B if applying B first would change what A does, what it applies to, or whether it applies at all — and the two are in the same layer. Dependent effects wait; the effect they depend on applies first, regardless of timestamps. If effects depend on each other in a loop, dependency is ignored and timestamps decide.

A CDA defines a characteristic (usually P/T, color, or type) from information about the object itself, and it functions in all zones, not just the battlefield. In the layer system, P/T-defining CDAs are applied in layer 7a — before set effects, counters, and modifiers. A card that is "*/*" where * counts something is using a CDA.

An object's timestamp is set when it enters the battlefield (or when an effect starts applying). A few resets matter:

• When a permanent changes control, it gets a new timestamp.
• A copy effect (layer 1) sets the copiable values before anything in later layers; counters and other-layer effects then apply on top and are not copied.
• Auras/Equipment attaching or effects beginning to apply establish new timestamps too.

Humility ("All creatures lose all abilities and are 1/1") layered with an anthem is a canonical test. Humility removes abilities in layer 6 and sets P/T to 1/1 in layer 7b. An anthem like Glorious Anthem ("+1/+1") applies in layer 7d, after the set. So under Humility + Glorious Anthem, creatures are 2/2 with no abilities. The order of the layers — not the timestamps — produces the surprising result.