Tower-Type Event

Tower Events are events that allows you to proceed to the next floor by acquiring a floor pass from defeating floor bosses and rune bosses. You can obtain floor rewards and unlock upper levels as you go to the next floor. The higher floor you enter, the better chance of obtaining better rewards. Ranking is based on the highest floor reached.

Overview
1 Tower Battle Point (Tower BP) is required to start a round battle. Tower BP recovery is 1 per 45 minutes. Full Tower BP recovery takes 3 hours & 45 minutes. The length of round battles is 30 minutes, while rune boss battle is 20 minutes. The level of difficulty determines the number of fights per round battle. If all the units have been used and you are not able to finish all the round in one BP, you will be asked to continue. Continuing with another BP gives a Continue Bonus which provides +50% to ATK/DEF. A second continue bonus, if the first one is not over yet, resets the time of the bonus but provides  another +50% to ATK/DEF, and can bring the total continue bonus to up to 200%.

Rune Bosses
Rune Bosses have a chance of appearing after winning a Final Round. You have 20 minutes to defeat a Rune Boss.

1 Tower BP is also required to start a fight against Rune Bosses. The number of teams that can be used to fight against the Rune Boss is depending on the level of difficulty where the Rune Boss had spawned.

Aside from floor passes and various rewards, runes can be obtained from defeating Rune Bosses. Each runes has it's own special effect and the effects are as follows:
 * 1) Yellow - Soldiers +10%
 * 2) Blue - DEF +100%
 * 3) Red - ATK +50%

The green Rune instantly recovers a BP if found in the treasure box. It can be found at any time, not just Rune Boss battles, and does not count towards Rune Time. Finding a green rune will also reset your Tower Battle Point recovery timer, so if you had 5 minutes left to recover a battle point, after collecting the Rune your timer will indicate 45 minutes.

Clarification on the Green Rune:

As per response of MyNet, the Green Rune is still unofficial and it is not possible for any players to obtain this Rune yet. For reference, see this screenshot of their reply.

After collecting 5 runes, you will enter Rune Time. The effect of the runes collected doubles. In addition, more rewards can be obtained! At the end of Rune Time, runes previously earned disappears.

KO Gauge
A new feature called KO Gauge has been added. The KO Gauge reduces as you attack the main boss. When the gauge is emptied, you will enter KO Chance period. The higher the rarity of the card, the larger amount of damage can be dealt in reducing KO Gauge. Attacking with opposing element deals 2x damage.

Combo Damage
Cards with Turn Skip Skill can be used to inflict a series of attack called COMBO. Every attack to the main boss increases the damage dealt to the KO Gauge by 10. When 7 Combo is reached and above, the damage dealt to the KO Gauge can go as high as 350.

KO Chance
During KO Chance, attacks inflicted break the damage limit, allowing you to deal large amount of damages. A card not in burst mode can deal up to 5M DMG, regardless of element and rarity. In burst mode, GSR and GUR cards can deal up to 10M DMG per hit while GLR cards can deal up to 30M DMG per hit.

KO Chance lasts for 5 turns. After the 5 turns, if the main boss/rune boss is not defeated, the KO Gauge returns at full amount so it is better to take them down while in KO Chance.

Maximizing Rune Time
Since is quite expensive, some players, assuming you have time to spare and don't mind the hassle, might want to maximize Rune Time by using this method.

Precaution: This method will keep you away from the Kingdom Screen and others, so collect resources, start Treasure Hunts, build Structures, etc. This also requires you to set a timer and keeps tracking of it. Note:  If VC Crashes when you return, re-opening it and going to the main "Tower Screen" should land you on the Rune Get screen.
 * 1) When you have 3 or 4 Runes, wait till you have 5 BP.
 * 2) Start a fight on your select level difficulty, at the same time keeping track of the time you started, 4 BP Left.
 * 3) If Rune Boss didn't appear after winning the fight, go back to Step 1.
 * 4) If Rune Boss Appear, Start Fight with Rune Boss, 3 BP Left.
 * 5) Kill the Rune Boss, proceed to "Victory Screen", and then "Reward Screen" which will show all the Floor Passes won. Keep it like this and don't do anything yet. Proceed to the next step.
 * 6) Sleep Device or "Exit" VC As follows(Depends on whether you need to use your device)
 * 7)  "Exiting" VC: "Exit" VC by pressing "Home" Button on your Tablet/Phone
 * 8)  Sleep Device without closing VC: Remain in the same "Reward Screen" and "Off the Screen of your Phone/Tablet"(Usually by Pressing Power button once). You can also close the game completely here. When reopening the game, as long as you do not re-enter the Tower, you will not gather the Rune (thus not triggering Rune Time). This will allow you to do other activities in the game such as treasure hunts, mini games, or kingdom and deck management.
 * 9) Once your Timer/Time indicates that your 2 BP used is restored (i.e., 1 hour 30 min has passed after you start the first fight), open VC, tap "Battle Finished" button and collect your rewards.
 * 1) If everything goes well and Rune Boss gave you enough Runes for 5 Runes. Rune Time will start and you will have 5 BP to use.

P.S.:
 * Some fights give a Tower BP restore after winning, so factor that in your time tracking if you happen to get 1. Getting one BP resets BP recovery so start counting at 45 minutes again.
 * This also works by "Parking" at the "Floor+Ranking Update Screen" but it's safer to "Park" at the "Reward Screen" in case of accidental taps at the Screen.
 * If you keep VC running while waiting for full BP recovery, setting a timer is no longer necessary since MyNet has already implemented a notification when Tower BP is fully recovered (unless you have unchecked the in-game notification or disabled app notification in your phone settings).

Tower Event Timeline
This is the timeline of the Tower-Type Events and their related event cards.