Herald of Serra

Echo is a triggered ability. “Echo [cost]” means “At the beginning of your upkeep, if this permanent came under your control since the beginning of your last upkeep, sacrifice it unless you pay [cost].”

Urza block cards with the echo ability were printed without an echo cost. These cards have been given errata in the Oracle card reference; each one now has an echo cost equal to its mana cost.

Flying is an evasion ability.

A creature with flying can’t be blocked except by creatures with flying and/or reach. A creature with flying can block a creature with or without flying. (See rule 509, “Declare Blockers Step,” and rule 702.17, “Reach.”)

Multiple instances of flying on the same creature are redundant.

Vigilance is a static ability that modifies the rules for the declare attackers step.

Attacking doesn’t cause creatures with vigilance to tap. (See rule 508, “Declare Attackers Step.”)

Multiple instances of vigilance on the same creature are redundant.