The Sunken Citadel

: With the Lord of the Sea by our side, we have prevailed in battle! However, the Deep Devils may yet have the last laugh: they have awakened Leviathan, the evil deity of the depths they worship. If Leviathan attains its full power, there is nothing in the world that can stop it.
: No time to regroup or recover, we must head into Leviathan's lair, the city of Ryly'eh, once the seat of Regnos' rule. It is time to defeat the Deep Devils and their malevolent god once and for all!
The Sunken Citadel is an elite stage in Kingdom Rush: Frontiers, and the third and final stage in the Rising Tides mini-campaign.
==Campaign==
===Set-Up===
* Gold 1700
* Strategic Point x13
* Shrine of Regnos x1
* Sea
===Wave Composition===
KRFstage18-1.jpg
Wave	Enemies(West > South)[Path]	Enemies(West > South)[Water]	Enemies(North > South)[Water]	Enemies(North > South)[Under Bridge]	Enemies(North > Southeast)[Path]	Income
1 	Greenfin x12 	 	Greenfin x16 	 	 	560
2 	 	 	Greenfin x12Redspine x2 	 	Greenfin x9 	500
3 	Greenfin x9 	Greenfin x7 	 	 	Greenfin x10Redspine x1 	560
4 	Greenfin x14 	 	Greenfin x3Blacksurge x1 	 	Redspine x4 	550
5 	Greenfin x12Redspine x1 	 	Greenfin x16Blacksurge x2 	 	 	700
6 	Greenfin x9 	 	Bloodshell x1 	Deviltide x9 	 	480
7 	 	Redspine x3Deviltide x6 	 	 	Greenfin x8Bluegale x1 	460
8 	Redspine x4 	 	Blacksurge x1Bloodshell x1 	 	Greenfin x4Bluegale x3 	590
9 	Greenfin x9 	Greenfin x13 	Greenfin x13 	Greenfin x13 	Greenfin x13 	1220
10 	Redspine x3Bluegale x2 	 	 	Redspine x2Deviltide x8 	Greenfin x9Bluegale x2 	780
11 	Bluegale x3 	 	Redspine x1Bluegale x3 	Redspine x1Bluegale x3 	 	620
12 	 	 	Bloodshell x3 	 	Bloodshell x2 	600
13 	Deviltide x9 	Deviltide x13 	Deviltide x13 	Deviltide x13 	Deviltide x13 	1220
14 	Greenfin x15Deviltide x6 	Blacksurge x3 	 	 	Bluegale x1Bloodshell x2 	870
15 	Bluegale x4 	Bloodshell x1 	Redspine x8Bluegale x2 	Redspine x2Bluegale x1 	Bluegale x1Bloodshell x2 	1240
Leviathan appears at the northeast corner to attack after wave 15. This is not counted as a wave.
- 	Enemies(West > South)[Path] 	Enemies(West > South)[Water]	Enemies(North > South)[Water]	Enemies(North > South)[Under Bridge]	Enemies(North > Southeast)[Path] 	Income
Boss fight	Deviltide x21Redspine x6Bloodshell x5Bluegale x1	 	 	Greenfin x10Deviltide x4 	Greenfin x20Redspine x4Deviltide x9Bloodshell x5Bluegale x1	3000
Strategy
===General===
This level is home to several powerful enemies with steep resistances. Great quantities of physical and magic damage are necessary if player is to pass this level (especially with 3 stars), but players can't afford to neglect stalling either. Fortunately, the Shrine of Regnos is a great help in dispatching stronger enemies, particularly when clumped together. It's too slow to be relied upon too much however, so players should hold off on investing in it until their setup is already reasonably solid.
Leviathan's tentacles will appear at several points in the level and wrap around your towers, disabling them. Because of this it's best to limit your use of costal strategic points to non-critical towers or barracks whenever possible. By the time he appears and the boss battle begins, you've already won. Leviathan himself has a relatively small health pool and any setup strong enough to survive the previous waves can easily dispatch him.
===Upgrades and Hero===
The water-covered portions of the map are impassible to most heroes, meaning they'll be restricted to the island on the bottom edge of the map, where they spawn. The only exceptions are those who can teleport (Nivus and Dierdre) and flying heroes (Ashbite and Bonehart) aswell as Saitam and Karkinos. The two dragons also deal almost exclusively True Damage, making them effective against the heavily armored Blacksurges and Bloodshells and the magic-immune Bluegales. They even expedite the boss fight by flying to Leviathan when he appears and attacking directly.
===Towers===
Necromancers may be a tempting choice due to their mix of damage and stalling power, but be wary. The skeletons they summon have little health and can easily be wiped out by Bluegale's storms, but they are very effective for stalling enemies like Greenfins in earlier rounds.
High level barracks, particularly tier 4 barracks towers are recommended. Assassin's Guild is very useful against stronger enemies like Bloodshells, Redspines and Blacksurges since they are capable enough of dodging attacks and plus if player decides to upgrade them with Counterattack, they can significantly increase dodge chance ( 70% chance at highest level) and also doing that, players can increase damage too. Sneak Attack is another highly useful upgrade, since with it, players are able to instantly kill enemies with chance that varies from 3-5%, which may seems like a small chance, but keep in mind that there are 3 Assassins, which means that Instant Kill chance is tripled. Also, even if Sneak attack fails, it will deal good amount of True Damage.
One Tribal Axethrower tower per choke point can also provide a much-needed boost to DPS and mitigate the impact of Blacksurges' and Bluegales' special abilites with Totem of Spirits and they can increase damage dealt to enemies with Totem of Weakness which is very useful for enemies like Bloodshells and Bluegales.
Artillery towers are not recommended for this stage !
==Heroic Challenge==
===Set-Up===
* Gold 1800
* Strategic Point x13
* Archmage Tower x1 (Unsellable)
* Sea
**Restriction: Heroes are allowed.
**Restriction: Upgrades fully allowed.
===Wave Composition===
KRFstage18-2.jpg
Wave	Enemies(West > South)[Path]	Enemies(West > South)[Water]	Enemies(North > South)[Water]	Enemies(North > South)[Under Bridge]	Enemies(North > Southeast)[Path]	Income
1 	Greenfin x12 	 	Greenfin x12 	 	 	480
2 	Deviltide x16 	 	Greenfin x16 	 	Greenfin x12 	880
3 	Greenfin x10 	 	Greenfin x12 	Redspine x2 	Deviltide x10 	720
4 	Deviltide x11 	Bluegale x2 	Greenfin x13 	Blacksurge x1 	Bloodshell x1 	770
5 	Bloodshell x1 	Bluegale x4 	Greenfin x21 	 	 	780
6 	Bloodshell x2 	Bluegale x3 	Greenfin x19 	Blacksurge x2Greenfin x3 	Bloodshell x2 	1200
Strategy
===General===
===Upgrades and Hero===
===Towers===
==Iron Challenge==
===Set-Up===
* Gold 3500
* Strategic Point x11
* Shrine of Regnos x3 (level 1)
* Sea
**Restriction: Heroes are allowed.
**Restriction: Upgrades fully allowed.
**Restriction: only.
===Wave Composition===
KRFstage18-3.jpg
Wave	Enemies(West > South)[Path] 	Enemies(West > South)[Water]	Enemies(North > South)[Water] 	Enemies(North > South)[Under Bridge]	Enemies(North > Southeast)[Path]	Income
1 	Blacksurge x7Bluegale x3Bloodshell x1	Greenfin x15Bluegale x2 	Blacksurge x7Redspine x2Greenfin x4Bloodshell x3Bluegale x2	Greenfin x33 	Greenfin x88 	4480
Strategy
===General===
===Upgrades and Hero===
===Towers===
==Related Achievements==
 SQUID IN ITS INK Defeat Leviathan, the Underwater God.
==Trivia==
* The name of the city, Ryly'eh, is a reference to R'lyeh, the nightmare corpse-city that appears in the H. P. Lovecraft short story The Call of Cthulhu, where Cthulhu sleeps, dreaming.
* On the map, the level flag is placed on a location named Mompoey Island, which is named after Pablo Realini Mompoey, one of the co-founders of Ironhide Game Studio.
* On the beach near the water-side exit flag, is a half-buried stone hand. This is a reference to a famous sculpture called The Hand by Chilean artist Mario Irarrázabal. It is located in Punta del Este, in Uruguay, which is where Ironhide Game Studio is based.
* The level preview shows a slightly different layout to the level as it is actually presented. "The Hand" is located on the beach near the land exit in the preview, whereas in the gameplay level it has moved over to the right, away from the battle. Its repositioning suggests that another Strategic Point was needed.
Category:Kingdom Rush: Frontiers
Category:Levels
Category:Elite Levels