The first time a player enters the Underworld, they will be prompted to enter a username. Only Latin letters and numbers can be used, within a 3-10 character frame (no spaces). Once a player confirms their username, it cannot be changed.
Each boss has a shield and the players must destroy it within a given time frame before they can finish the boss. After all the shield is destroyed, players can finish the boss in a final one-on-one battle. If they lose the final fight, they can repeat it until they win. Each raid fight consists of one round, lasting 45 seconds. Players can buy or obtain several items like charges of darkness and potions to aid them to deal additional damage or survive longer. There are certain things that make the raid fights differ from other fights:
- The level and stats of all equipment does not affect raids.
- No perks work in raids.
- Underworld bosses are more aggressive than other enemies.
- They are immune to the Stun enchantment.
In the first tier of the Underworld, there are four bosses.
Special Bosses Edit
They are the special bosses encountered in the first floor, available to be fought during the special events of the game (Halloween, Christmas, New Year... etc). Fights with them carry random rules in each round.
Underworld : Tier 2 Edit
Underworld: Tier 3 Edit
This tier has one boss whose name and appearance is currently unknown.
??? - Requires Dan 8
Charges of Darkness are items that can deal damage to the bosses. They work like thrown Magic, except for the Large Charges, which have a unique animation. When throwing a Charge, the character will become invulnerable to melee attacks.
- Minor Charges of Darkness
Deal a random damage between 75-84. Can be bought for 5 gems. It is the easiest charge to get. Player can get it as reward from beating any Eternal, daily quests, first place chest, and at the end of a season.
- Medium Charges of Darkness
Deal a random damage between 500-531. One can be bought for 25 gems, while 10 of them only cost 175. It is harder to get (compared to the small charges). Player can get it as reward from difficult daily quests, at the end of season, and by defeating Fungus, Vortex, Fatum, Arkhos, and Hoaxen.
- Large Charges of Darkness
Deal a random damage between 1000-1021. One can be bought for 35 gems, while 10 of them only cost 299. It is the hardest charge to get. Unlike the small and medium charges, the large charge cannot be dodged. Players can get it by reaching first place in raids with Arkhos and Hoaxen.
Elixirs are items that can give a buff to the players. They last one round, and only one can be used at a time. There are different types of elixirs, with each type giving a unique buff.
Players can withstand any Critical Hit without falling to the ground, similar to the Rock perk. Can be bought for 15 gems or 50 Coins of Love.
- Magic Source
Every hit taken will increase the players' magic recharge, similar to the Magic Recharge enchantment. Can be bought for 15 gems or 50 Coins of Love.
- Steel Hedgehog
Each time the players take a hit, they will reflect a percentage of damage to the enemy, similar to the Damage Return enchantment. Can be bought for 15 gems or 50 Coins of Love.
Player will receive rewards at the end of a season, which last for three days. The rewards depend on the players' score and position at the League leader-board. The rewards are a supply of small and medium charges, raid keys, and a small amount of gems. Players at the 1st-5th place also have a chance to get a random item from the Monk's Set. The Monk items obtained this way will only be enchanted with tempest rage (no simple enchantment)
- Main article: Dan (SF2)
Dan is a level-like system. All players start with Dan 1. By accumulating enough score, they will receive a Dan promotion at the end of the season, along with additional rewards. Higher Dan allows players to fight bosses with Dan requirements. Currently, the highest Dan is 7.
- Main article: Clan (SF2)
Player can join a clan or create their own clan in Underworld. Being in clan will give player the advantages to fight bosses together with their clan members. It also provides a better chance to gather players during match-up.
- Using certain weapons may allow the player to perform better in raids.
- Obtaining Ranged Weapon and Magic can increase the player's performance. Ranged weapon is unlocked after defeating Lynx, and Magic is unlocked after defeating Hermit.
- Enchantments can increase the player's performance. Players can enchant their equipment with Shadow Orbs that can be won from eclipse mode, or they can use pre-enchanted equipment such as the Monk's set, demon weapons, special event weapons, and gem-purchased equipment.
- Charges can help players in dealing damage.
- Collecting the Monk's Set will unlock the Mythical enchantment Tempest Rage. Monk's Set and Tempest Rage can increase the player's performance greatly.
- Soon after the launch of the multiplayer mode the strength of the bosses' shields was decreased. However the damage they dealt was instead increased.
- All Eternals wield gem weapons.
- If the two first players in a raid deal the exact same amount of damage, they will both get the first place reward at the end (if they win the raid).