There are many different builds, which one you use will depend on what you're trying to accomplish and how far into the game you are:
Intermediate builds assume you are near the end of a legend and have a lot of gold to spare, or will help you get more. They often use pets and key items that need to be built up as well. They don't use epic equipment since you're expected to legend some more and epic coins are what persist through a legend, not the equipment itself.
Advanced builds readily use epic coins. They are for completing the daily dungeon in a single attempt, powering through mastery stages, you also have a safe spot where you take a break and have the lucky fountain and you also have a shop where you by potions and weapon etc and completing story mode challenges. They also focus on items that get consumed.
Specific builds are for beating special challenges, such as some of the mini games and daily dungeons that have restrictions.
Other builds are mostly gimmicky and for fun. They include some of the theme gear like all the "ninja" gear, or all the "airstream" gear.
Speed Boost Build Edit
Requirements: Poison Dagger, Track Suit, Swift Boots, Pocket Watch
Optional: Apprentice Sword
Minimum Level/Gold: 5, 5000?
Playstyle: Swing your sword as much as possible. The goal is to reach as far as possible, die, and reset many times. Eventually buy the Haste Spell and switch out some pieces of gear for stronger damage or charge.
Notes: This is an incremental build, buy any of the pieces you can, as soon as you can. You don't need the complete set for it to work.
charge, best for short bursts like completing story mode stages, fresh legend
Grind Stone Build Edit
Purpose: Daily Dungeon or Endless Mode
Requirements: Weapon with High Range, Grind Stone, Skill:Efficient Packing, Skill:Quick Usage, Health Potions.
Recommended stats are Defense and Health
Optional: Airstream Runes and Support Spells.
Playstyle: Use Grind Stone whenever it's off cooldown, attack as much as possible, don't forget to block projectiles.
Notes: Grind Stone boosts your weapon damage for a period time. However that buff is multiplicative and also stacks with previous uses of Grind Stone. If you use Grind Stone again before the buff wears off your weapon's damage will be increased permanently and eventually those small changes become large margins.
This means that your weapon damage can be raised infinitely as long as you have access to the item.
Holy Spell Build Edit
Requirements: Arcane Staff, Wizard Mantle, Wizard's Book, Sorceror's Orb. Health and Mana potions. Holy level 6, Lightning level 6, Haste level 3. Owl level 6 Fireball+Ice Nova+Recover spells, Wizard Mantle, Arcane Staff, Wizard's book+Sorceror's orb, Warrior's Drink+Mage Juice
Minimum Level/Gold: 30? 450k?
Barrier Spell Build Edit
Same as Holy Spell build, but replace Holy with Blade Barrier. Keep Blade Barrier and Haste up always, save Lightning for big groups and bosses. Needs more gear maybe, enough int to make strong? advanced build?
Brainless Blitz Build Edit
Purpose: Story Mode (+Mastery levels), Power Leveling at Goblin Horde.
Recommended stats for remaining equipment slots are Defense, Mana Cost Reduction, Mana.
Items: Bomb Brigade, Health/Mana Potions.
Optional: Mana and Health Runes.
Playstyle: Cast Haste and Blade Ring continuously, When enemies get stuck on you or there's too many for Blade Ring to keep them off you, cast Ice Nova. Use Bomb Brigade on bosses to win quickly, They only cost 1,000 Gold Each, does a ton of damage in a very short span of time AND has a low downtime.
Important Note: If you don't have a lot of defense, block projectiles as best as you can. And for areas with spiders it's better to equip the Venom Gland for poison immunity so that you don't have to even bother blocking venom projectiles.
distance, daily dungeon, mastery modes burst for store mode stages, fire hydra epic, lightning epic, meteor epic,
Requirements: Molten Mace, Ember Robes, Fire Pendant, Hydra's Heart. Hydra level 6, Fireball level 6. Dragon level 6.
Minimum Level/Gold: 80, 14000 epic coins for gear, 2500+? for spells.
Playstyle: Use both spells and pet ability on cooldown.
Crit Stuff : Maxed Hydra's Fang, Rogue's Kit, Pegasus Treads & Pocket Watch ; Blade Ring, Haste, Chakra (for sustain and long runs) or Berserk (for short runs), Dragon is usefull for upgrade your damage and deal dmg to far opponents.
Runes : 4 yellow runes is a must have, the more stats you will have in your rune page will rise your damage sharply. If you have purple and Yellow ones it's nice.
Minimum Level/gold : 40 (if you payed or if you are really good at the game) - 60, Maxed Hydra's Fang is quite long to have it could cost you a lot if you decide to upgrade it with Epic Coins. More than 500k Gold for the stuff and spells.
Take Health pot and MP pot with Elixir or NRG Drink (Yes it's quite stupid but in Daily dungeon it's Juicy (don't spam it)).
Playstyle : Use your spells and hit when mobs get too close to you, for bosses try to use NRG drink before they come near to you for hitting them badly, else use your Dragon for hitting them instead.