Corrupted Sword

Corrupted Sword
Type	Melee, Projectile
Description	Slashes in both directions. Deals increased damage at low HP.
Unlock	Upgrade the Cursed Tome to Level 20 within 10 minutes of starting a run.
Upgrades With	Damage, Projectile Count, Projectile Speed, Size
Silver Reward	8
Special Effect	Damage is reduced at high HP, but significantly increased at low HP.; Fires a ranged slash projectile behind you.; Projectiles pierce enemies.

The Corrupted Sword is an endgame weapon in Megabonk, designed for expert players who favor a high-risk, high-reward "berserker" playstyle. It offers immense damage potential in exchange for requiring the player to maintain low health. Its unlock condition is one of the most difficult challenges in the game.

The backwards slash deals half the damage of the forward slash, but has a much longer range.

How to Unlock (Challenge Guide)

Unlocking the Corrupted Sword requires speed, luck, and a deep understanding of game mechanics.

Prerequisite: First, you must unlock the Cursed Tome. This is done by finding and defeating a stage boss in under 5 minutes.

Once the Cursed Tome is available in your item pool, you must complete the main challenge:

Start a new run and hope that the Cursed Tome is offered as one of your first few tome choices. If it's not, it's often best to restart the run.
Once you have the Cursed Tome, your only goal is to level it up to 20 as fast as possible.
Prioritize XP Gain: Focus exclusively on upgrades and other Tomes that increase your Experience gain. This will allow you to level up faster and get more chances to upgrade the Cursed Tome.
Use Refresh and Banish: Actively use your Refresh and Banish options to get rid of any offered upgrades that are not levels for the Cursed Tome or XP boosts.
You must reach Level 20 with the Cursed Tome before the in-game timer hits 10:00.

After completing this difficult challenge, the Corrupted Sword must be purchased from the Unlocks tab for 8 Silver.

Strategy and Synergies

The Corrupted Sword has damage scaling based off of your current HP. It deals heavily reduced damage at high HP, and significantly increased damage at low HP. Below you can see a table displaying the exact damage modifier at each current HP %.

Current HP % Damage Modifier
HP	Damage	HP	Damage	HP	Damage	HP	Damage	HP	Damage
100%	x0.4	99%	x0.4	98%	x0.4	97%	x0.401	96%	x0.403
95%	x0.405	94%	x0.406	93%	x0.409	92%	x0.411	91%	x0.415
90%	x0.418	89%	x0.422	88%	x0.426	87%	x0.431	86%	x0.436
85%	x0.441	84%	0.447	83%	x0.453	82%	x0.46	81%	x0.466
80%	x0.474	79%	x0.481	78%	0.489	77%	x0.497	76%	x0.506
75%	x0.515	74%	x0.525	73%	x0.535	72%	x0.545	71%	x0.555
70%	x0.566	69%	x0.577	68%	x0.589	67%	x0.601	66%	x0.614
65%	x0.626	64%	x0.64	63%	x0.653	62%	x0.667	61%	x0.681
60%	x0.695	59%	x0.71	58%	x0.726	57%	x0.741	56%	x0.758
55%	x0.775	54%	x0.791	53%	x0.808	52%	x0.825	51%	x0.844
50%	x0.862	49%	x0.88	48%	x0.9	47%	x0.92	46%	x0.939
45%	x0.96	44%	x0.98	43%	x1	42%	x1.022	41%	x1.044
40%	x1.065	39%	x1.088	38%	x1.11	37%	x1.134	36%	x1.157
35%	x1.181	34%	x1.205	33%	x1.23	32%	x1.255	31%	x1.28
30%	x1.306	29%	x1.332	28%	x1.359	27%	x1.385	26%	x1.413
25%	x1.44	24%	x1.468	23%	x1.496	22%	x1.525	21%	x1.555
20%	x1.584	19%	x1.614	18%	x1.644	17%	x1.674	16%	x1.705
15%	x1.736	14%	x1.768	13%	x1.8	12%	x1.832	11%	x1.865
10%	x1.898	9%	x1.931	8%	x1.965	7%	x2	6%	x2.035
5%	x2.07	4%	x2.105	3%	x2.14	2%	x2.176	1%	x2.213
When at exactly 1 HP, Damage multiplier is set to x3

Shield bonuses: Whether they are from Charge Shrines, the Chaos Tome, or even the Shield Tome having any amount of shields will prevent you from dying to a single hit regardless of how low your HP is.
Mirror: Prevents you from taking damage from a hit and briefly makes you invincible. This is just as effective as Shield and can stack with them, just be mindful that this item has a cooldown before it can be activated again.
Kevin: Kevin has a chance to damage you when hitting enemies. This damage cannot kill you, ignores Shields to damage your HP directly, and doesn't trigger the Mirror. Perfect for keeping your HP at 1 for the maximum damage bonus without disrupting your other methods of survival.

Best Characters:
- Athena gains damage at low HP just like the Corrupted Sword so they pair together better than most. She also starts with the Aegis weapon which can keep you from dying if you take a hit while at low HP. Just remember that at least 1 damage will still be taken through the Aegis' protection.
- Noelle gains 1% Size per level which helps your slashes hit more enemies. She also starts with the Frostwalker which will freeze enemies, slowing them down and keeping you safer.

Upgrades

The Corrupted Sword can receive the following upgrades upon leveling up:

Stat	Common	Uncommon	Rare	Epic	Legendary
Damage	2	2.4	2.8	3.2	4
Projectile Count	1	1.2	1.4	1.6	2
Projectile Speed	4	4.8	5.6	6.4	8
Size	15%	18%	21%	24%	30%