The Dark Avenger Infinity Tower is one of the best places to earn gold and the only place to find Ancient Medal. The only down side is that you will not earn any experience. To gain Ancient Medal in the Infinity Tower you have to find a random boss that has a chance of dropping some upon defeat. You know when you find the special boss as there will be a big pop up notice saying “Event Boss” telling you just before you fight it. If you don’t get and Ancient Medal fro the drop you will get around 30 BP point instead. You will also get a reward of BP points depending how high you get in the tower. Spending 3 key to start at 61 while automatically get you a high score around the top 30%.
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There is a timer that is always counting down and when the time or your health reaches zero your run is over and you keep all items and gold found and earned. The maximum of time you can have is 60 seconds or 1 minute. You will usually loose most of your time on boss battles later which will give you the most risk draining the clock. Killing large groups fast is the best way to refill the timer.
You are limited to 10 keys per day that you can use to enter certain floors. For 1 key you will start at floor 1, 2 keys to start at floor 31, and 3 keys to start at floor 61. Going from the first floor to the 50th will net you about 10,000 gold and an Event monster taking about 30 minutes or so depending on strength.
You can not bring any health or mana potions with you and there are no healing fountains so try to avoid damage as much as possible to maximize longevity.
The chance of getting a boss floor are random and you can fight several in a row. Bosses will always appear in the north part of Tower floors and every floor looks the same.
Warning: If you loose your internet connection while inside the Tower after you beat the floor you will get a message to Save Later or Retry, if you choose Save Later you will be kicked from the tower. The best thing you can do is try to get your internet connection back without closing the game.