Onyxia Mission Guide

Onyxia’s Army

• Drake
• Gargoyle
• Gryphon Rider
• Necromancer
• Spiderlings
• Warsong Grunts

Currently, there is no Heroic version of Onyxia. Therefore, none of her minis have talents, as regular campaign mission minis do not have talents.

Onyxia’s Stats

• 18,000 Health (level 1)*
• 375 Elemental damage (level 1)
• 12 range - only a Meat Wagon with the range talent can outrange Onyxia
• 4-second attack speed

*When comparing stats in Rumble, it is common to use level 1 stats. Everything scales exponentially, so level 29 vs level 30 is the same difference as level 1 vs level 2. Comparing level 1 stats keeps the numbers more manageable.

Onyxia Battle Phase 1

The very beginning of the battle can already be difficult. In campaign missions, the hands of both the boss and the player are randomized once, and then that same random seed stays until you win. The opener you see from Onyxia depends on her opening hand.

You can change your own opening hand by moving your minis to other slots after you have fought Onyxia once. The randomization is based on the army slots, not on the minis in them! You cannot change when you will get your Kobold and your Leader, but you can move everything else around to get a better start.

In the first phase, Onyxia will spawn groups of Whelp Eggs on the left and right lanes. The first set will spawn at 5:40 and new sets will spawn every 90 seconds. If left alone, the Eggs will automatically pop 30 seconds after spawning.

The Eggs spawn throughout the fight. Especially at lower levels, it is important to memorize their spawn timer to be ready to clear them as they come. You will get a grasp of it as you keep pulling Onyxia, but knowing when they spawn can help you stay on track more easily.

The spawn times are:

• 5:40
• 4:10
• 2:40
• 1:10
• 1:40 in overtime
• 0:10 in overtime

There are many options for clearing the Whelp Eggs. Most of them rely on clearing the Eggs before they hatch, but with some minis, you may also want to clear the hatched Whelps. These are some of the minis that have been used against Whelps:

• Witch Doctor is phenomenal at clearing Whelps and Whelp Eggs, if he has enough levels. He does better against the right side than the left side because of the way the Eggs are positioned. Try to keep him at the maximum distance to give him the most time to channel before Whelps get in range. Level 24 can clear the right side, but not the left side. Level 26 can handle both sides.
• Drake is very effective at clearing Whelp Eggs because it will also kill the Whelps themselves right as they spawn from level 23. It is less good against spawned Whelps because then they end up trading shots.
• Pyromancer is best used against spawned Whelps. She can one-shot Whelps from level 28, but can be useful even if she needs two hits to kill them. Conflagration is a useful talent to hit more Whelps at once.
• Firehammer can do Whelp duty if needed. She can one-shot Whelps at level 30, or already at level 25 if she has the Moultin’ Metal talent.
• Darkspear Troll is also an option for Whelps. He can one-shot them at level 26 and can become a very fast attacker if equipped with the Headhunting talent. (There are also some fun uses for Darkspear Troll with Big Bad Voodoo.)

You will also mine gold close to the Whelp spawns. A Drake will kill the Whelps as they spawn, creating a safe mining environment, but a Witch Doctor cannot keep a Kobold alive. You still want to send Kobolds as often as possible, alternating between the left and the right lane. Wait just enough to make sure they do not get killed.

Onyxia’s gold income in phase 1 is only 0.2 gold per second, far below player gold income. Her income increases with each phase, which is why you want to stay in phase 1 as long as possible - given that you will also need some time to get through the other two phases.

You spend phase 1 taking control of all the towers and preparing any static defenses you may have, such as Skeleton Party with Ritual of Rime, Whelp Eggs, Drake with Mother Drake, or Drake with Roost.

Onyxia Battle Phase 2

At the start of phase 2, Onyxia will knock back your minis and destroy all of your minis at the upper part of the map, as well as the two top towers. You can immediately start to reclaim the upper Towers if you have Whelp Eggs or Eggs from Drake’s Mother Drake talent nearby: the Eggs will pop, and the Whelps will survive.

The knockback effect is interesting: how far minis are knocked back depends on their weight. The knockback happens before the board clear, so light minis can be thrown out of the danger zone and end up surviving. You can even place Skeleton Parties right below the top two towers and they will be knocked back far enough to survive because they are so light. They will also walk back to their original place, yes even with the Rime talent, retaking the Towers. As a downside, they do a poor job of defending the Towers otherwise when they are so far back.

Onyxia gains the Resistant trait at the start of phase 2, and will now only take 50% Elemental damage.

Phase 2 adds a new cave-in mechanic, which spawns a group of four Earth Elementals around the map at the start of phase 2 and then every 50 seconds thereafter. The Whelp Egg spawns continue: these two spawn timers may sometimes coincide, depending on when you enter phase 2.

Onyxia’s gold income in phase 2 is 0.3 gold per second, close to what a player gets and a 50% increase to what she had in phase 1.

Your goal in phase 2 is to retake the Towers and prepare your next attacks. As you prepare to push into phase 3, you may also want to prepare your final push: if you send your push from your base, you can build it up and also start building another push already before phase 3 begins. Note that the upper part of the map is wiped at phase changes, so your final push must not reach the part of the map that gets wiped before the phase has changed again.

Especially at lower levels, you want to push Onyxia to phase 3 at the start of overtime or close to it. The exact timing depends on your strategy and the damage output of your minis, so you will need to play with the encounter with your own army to figure it out. Start of overtime is a good general idea.

Onyxia Battle Phase 3

At the start of phase 3, Onyxia will again knock back your minis and destroy all of your minis at the upper part of the map, as well as the two top towers.

Onyxia gains the Armored trait at the start of phase 3, and will now only take 50% Physical damage. She also keeps the Resistant trait from phase 2, so she also only takes 50% Elemental damage.

At the start of phase 3, Onyxia summons two Onyxian Warders by her side. The Warders will start walking towards your base through the middle. The Warders are summoned only once and do not respawn.

Onyxian Warder:

• 2800 Health (level 1)
• Resistant (50% Elemental damage taken)
• 120 Elemental damage ranged aoe attack
• 9 range
• 1.4-second attack speed

The Earth Elemental and Whelp Egg spawns continue in phase 3.

Onyxia’s gold income in phase 3 is 0.4 gold per second, more than what a player gets and a full 100% increase to what she had in phase 1. She summons twice as many minis as she did in phase 1, on top of all the mechanics.

Your goal in phase 3 is to survive the assault and also take down Onyxia, who now takes less damage than before thanks to her newly-found Armored trait. One common way to lose the fight is to run out of time and end in a draw. Another way is to push the phases too early and get overwhelmed without the overtime gold. Finding the right timings for the phase changes for your army is one of the key aspects to winning the fight. With some comps, you may not need to even wait for overtime, whereas with others, you only have a small window to succeed.

Changes to Onyxia

Onyxia has received several bug fixes and buffs. Here are the most recent changes that have affected the encounter:

January 27, 2025:

• Earth Elemental Health increased to 1175 (was 940).

December 18, 2024:

• Onyxia clears all poison on phase transitions
• Onyxia receives a 5-second temporary damage reduction of 90% on phase transitions

July 30, 2024:

• Execute damage against Onyxia reduced to 3% at even level with a level modifier of 0.5% (was 5%)