Good to know it's not a limited time engagement. How does luck affect the drops since the top attacker gets a drop?
Luck does not play a role in the guaranteed drop that is awarded to a random "top attacker" by killing a Captain. It's completely random. The Lighthouse is a guarantee to everyone on the "top attacker" list, again luck not involved.
Where luck DOES come into play in a big way are the points you accumulate by killing creatures. The points are awarded based on the fame of the creature you kill grounded on the principle that the more difficult a creature, the more fame it will have. As you acquire more and more points your chances of getting a minor artifact drop approach 1 in 1.