FlyingFlying 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. (CR 702.9)
AscendAscend on an instant or sorcery spell represents a spell ability. It means “If you control ten or more permanents and you don’t have the city’s blessing, you get the city’s blessing for the rest of the game.”
Ascend on a permanent represents a static ability. It means “Any time you control ten or more permanents and you don’t have the city’s blessing, you get the city’s blessing for the rest of the game.”
The city’s blessing is a designation that has no rules meaning other than to act as a marker that other rules and effects can identify. Any number of players may have the city’s blessing at the same time.
After a player gets the city’s blessing, continuous effects are reapplied before the game checks to see if the game state or preceding events have matched any trigger conditions. (CR 702.131) (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Whenever this creature attacks, if you have the city's blessing, put a +1/+1
counterTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on it.