[Saber Cherry]

To summarize:

(note that I call a battle round a "phase" and a unit's turn a "turn", for clarity)

1) A unit can only target one square per turn.
2) For each weapon, he can attack any unit in that square.
3) If a weapon (like Flail or Sword of Swiftness) has multiple strikes, they will all be on the same unit. If you kill the unit with the first strike, the second strike will never be used.
4) Magical Quickness (+100%) is multiplicitively cumulative with Heroic Quickness (+unlimited%) and Blessed Quickness (+50%). Divide your effective action points (AP) in combat by your un-quickened AP to get a number (like 2.3). This is the number of turns your unit gets per combat phase (the extra .3 in this case carries over to the next round, until it builds up enough for 3 attacks in a round). Units with Quickness can target one square per turn.

Example: Neifel Jarl with 2 Swords of Swiftness, Water-9 blessing (+50%), casts Quickness on himself.

Result: 150% * 2 = 3 turns per phase. 2 swords * 2 swings each = 4 attacks per turn. Total = 3*4 = 12 swings per phase, on at most 6 targets, in at most 3 squares.

So he can move 3 times and target 3 squares each phase. However, he can only kill 2 units at most per turn, since he has only 2 weapons. If he is fighting Sea Trolls (which are size 4; only one per square) he can kill at most 3 per phase. But humans pack 3 per square, so he can kill 6 per phase.