Fusion is the process of merging heroes to a host. This serves various purposes including the increase of a hero's level and rank EXP (rEXP). Fusion costs gold, and the amount of gold increases per hero fused and by the rank of the hero put towards the fusion. Same-hero fusions also tend to cost significantly more than heroes fused to a different character.
Fusing towards Levels
All heroes can contribute to increasing the host's level, but you can increase the amount of EXP given to a hero by fusing higher-ranked heroes and/or higher leveled heroes. 100% of the EXP a hero has will transfer upon fusion (eg. fusing a level 50 Dober to a level 1 Felix will result in a level 50 Felix).
Even at level 1, different ranks passively contribute EXP themselves. A higher ranked hero will contribute more EXP than a lower ranked one. The rank bonus is added onto the EXP being transferred to the host.
Minor & Lesser Lexicons
The most commonly used heroes for fusion fodder are the lexicons and Books of Heroes, which are exclusively for fusion. Minor and Lesser Lexicons are attained through co-op Tower runs, while Books of Heroes come from various parts of the quest line. They are normally fused as-is.
None of these 'heroes' require training to be fused, although some players train a couple lexicons to level 50 if they have trained all their heroes so that upon gaining a well-sought hero, they can immediately fuse the lexicon to said hero and avoid training it manually to level 50. This is usually done in anticipation of new releases so that the player can immediately rank up its skill and use the hero.
Season 1 heroes have different EXP curves than Season 2 heroes. S2 heroes require 150% more EXP than a S1 hero to reach level 50; upon attempting to fuse a level 50 S1 hero to a level 1 S2 hero, the S2 hero will receive ~42 levels instead of 50. Note that 100% of the EXP is still transferred - S2 heroes simply require more EXP to reach level 50. S3 heroes require the same EXP as S2 heroes, thus fusing a level 50 S2 hero to a level 1 S3 hero will result in a level 50 S3 hero.
Fusing towards Promotion
Promotion EXP is shown as a blue bar (appropriately labelled "Promotion EXP") on a hero's portrait in the Heroes interface. The promotion bar indicates how close a hero is to promotion. Each subsequent rank requires an increased amount of rEXP in order to be promoted. Note that lexicons do not contribute to rank EXP, despite being ranks 1 and 2 respectively.
Amount of rEXP given based on hero's rank per card, if the card is the same as the host
| || || || || |
|250 rEXP||500 rEXP||1,000 rEXP||2,000 rEXP||4,000 rEXP|
Amount of rEXP given based on a hero's rank per card, if the card is different from the host (for S1 and S2 heroes)
|20 rEXP||40 rEXP||80 rEXP||160 rEXP||320 rEXP|
Amount of rEXP given based on a hero's rank per card, if the card is different from the host (for S3 and S4 heroes)
|40 rEXP||80 rEXP||160 rEXP||320 rEXP||640 rEXP|
When attempting to fuse S1 heroes to S2 heroes, all rEXP will be halved (exception: max. level fusion, see below). Despite this, S1 and S2 heroes require the same amount of rEXP to achieve promotion. S3 heroes, however, require twice the rEXP (quantitatively) to achieve promotion (not counting cross-season penalties).
Similarly, an S2 hero will only contribute half the normal rEXP when fused to an S3 hero, while an S1 hero will only contribute only one-fourth of the normal rEXP when fused to an S3 hero. When you consider that S2 heroes incur a 50% rEXP penalty, it becomes four times as hard. When fusing S1 heroes to S3, it is eight times as difficult compared to a S3 - S3 fusion because of the 75% penalty.
Here is the amount of rEXP you will have. Base heroes are on vertical, material heroes are on horizontal.
|Season 1||Season 2||Season 3||Season 4|
|Bonus lvl 50 to all season||500 (1000 in KLOH)||1000|
|Season 5||Season 6|
|Bonus lvl 50 to all season||1000|
Max. Level Fusion [Implemented in patch 1.4.21]
If a hero sacrificed for fusion is at the maximum level of 50, that hero will contribute an additional 500, 1000 or 1000 rEXP to the fusion host if the hero is S1, S2 or S3 respectively, along with the normal contribution based on it's own rank and season.
This bonus rEXP is unaffected by cross-season fusion rules. For example, a S1 rank 4 hero at the maximum level of 50, when fused with a host hero of S1, S2 or S3 will contribute 660, 580, or 540 rEXP respectively (i.e. a flat 500 rEXP bonus to the rEXP contributed at sub-maximal level).
This bonus is also not magnified if the host hero is the same as the sacrificed hero.
For example, fusing a max level Drake of rank 3, 4 or 5 with a host Blood Pearl will contribute 1160, 1320 or 1640 rEXP respectively (i.e. a flat 1000 rEXP bonus to the rEXP contributed at sub-maximal level).
This feature greatly reduces the effort for ranking up S2 or S3 heroes or even high ranking S1 heroes without depending on same hero bonus while also circumventing cross-season penalties.
The cost of the fusion depends on the level and the rank of the sacrificed hero.
- Fuse identical heroes, the sacrified heroes must be lvl 1(No Max Level Fusion for identical heroes)
- Fuse heroes from the same season, the sacrified heroes must be lvl 1
- One exception: season 2 (and season 1 for KLOH), rank 1 heroes must be level up to 50 before fusing with any season heroes.
Promotion occurs when the Promotion EXP bar is completely filled. When using the same card as the host, this is normally achieved by fusing 4 of the same cards to reach the next rank, then 8 for the rank after, 16 for the rank after that, etc. Any additional rEXP gained in fusion is carried over to the next rank (eg. 5 Dobers will promote the host Dober from 0 rEXP at Rank 3, and add an extra 1,000 rEXP for the next rank).
Amount of rEXP required for promotion per rank (Season 1 and 2)
Rank 1 > 2
Rank 2 > 3
Rank 3 > 4
Rank 4 > 5
Rank 5 > 6
|1,000 rEXP||2,000 rEXP||4,000 rEXP||8,000 rEXP||16,000 rEXP|
Amount of rEXP required for promotion per rank (Season 3 and onwards)
Rank 1 > 2
Rank 2 > 3
Rank 3 > 4
Rank 4 > 5
Rank 5 > 6
|2,000 rEXP||4,000 rEXP||8,000 rEXP||16,000 rEXP||32,000 rEXP|