You've finally killed Elban. You've unlocked Heroic Difficulty, which is just a re-hash of Normal, except the monsters give about 1.5x rewards but have about 4x health.
So what now?
The first thing you're going to want to do is hit max level on your main character. As of 11/19/2016, the highest level you can reach is 70. Once you're level 70, all the experience that hero earns goes towards your account's Champion Level (page about that will be created later). From then on, every new character you create, even the ones that haven't reached level 70, can access the perks that your Champion levels give.
Speaking of new characters, you should grab all 5 character slots as soon as possible. The third character slot costs 100 gems. The fourth slot costs 500 gems, and the fifth one costs 1000 gems. It might not seem worth it in the beginning, but remember that each character receives a daily quest which can easily be completed for a nice bonus of 20 gems and some exp for that character. Once you have all 5 character slots, you have a daily income of 100 gems, not to mention the gems you naturally pick up from playing the game. You'll break even in less than 2 weeks!
The Mage is a balanced endgame character for now. With a level 10 Arc Lightning spell and a high attack speed, almost nothing can touch the Mage. Your main attack is going to be Arc Lightning, which pushes things back a small distance. Combine this with a huge attack speed and the right spells, and you'll be unstoppable. The main spells you want are Blink and Time Warp. Blink is capable of multiplying your DPS by 3 if you use it correctly, and Time Warp essentially renders your hero unkillable. For the third spell, should you choose to purchase the slot for it, can be Singularity or Arcane Deflection. Both are very good when clearing huge hordes of enemies, but you should choose the one you need.
Beware of the upcoming arrows, as long Mage attack skills has limited range. You should aslo give some time on high defense, cause arrows can one hit you in higher trials. Block change isn't useful with this class.
In order to give you higher defense, you can go for freezing skills. They can be very useful as long they will make enemies frost for a certain amount of time. This can give you partial damage time where you can switch from frost blot to arcane bolts and just attack them till they can't move.
For the Companions, Maggie is a must. Without her, you can pierce elite auras and your Mage will then hit the roof. If not worried about this, try 3 Nogrims. They can rush into battle with their basic skills, that are same as Marcus have. However, these ones have higher toughness and can wage more hits from enemies, that you can easily use on your side, again with using of Arcane Bolts.
After putting on a complete sets of your choose, you can get high benefits from these ones and get higher opportunity of the battlefield.
When at the boss fights, you will need to manage with high damage from them. They can always one hit you at high trials, when without basic shield. Keep in mind, that holding distance in always useful. The best ranged skill is Frost Bean that is also useful at big enemy groups after the vortex combo.
Warrior is a good endgame character that can bring you loads of funny gameplay. His skills are mainly damage based and let's you to control the face to face combat from the near distance to your enemy. Try to focus on the high toughness so your survivability will be way higher as well buff you life on hit, which can be well merged with attack speed when fighting with two weapons. Best set refers to be Juggernaut's, however the Defender's is still holding it's rank title. Make sure your damage is viable for the speed clear in trial, with making some of bigger pulls of mobs.
Warrior has the defensive playstyle, and give it you aslo this show. Use celerity skills to high packs around you, bash is best on one to one elites and bosses (that are weak in damage but strong in their HP), and your frenzy is capable for high damage bosses and low HP ones. You can try cleave on one to one combat, but it does now compare with high damaging bash skill.
Parrying or blocking. Choose one of these. Parrying is when your warrior parries upcoming attacks with it's sword, making him untouchable. Blocking is only available with a shield. Both are very useful and gives you big chances of survival as long mobs just cannot touch you there on the Battlefield.
So, your choice was Bounty Hunter? If you like the ranged class, enjoy your veteran gameplay with this killing class. Remember, that your defense is really nerfed when compared to other classes and the range, attack speed and skill build keeps you alive. When doing the trials over 100, the defense utility skill is the must. Try the Smoke Screen to keep your enemies away and keep your position easily while in fight.
You should take care of high damage, as long your single DPS is grown way higher when using pistols. Critical rating is a great choice for this deadly class.
Attack skills? Well, if a range isn't your problem then definitely go for Scatter shoot. This skill shares many similarities with the Mage's Arcane bolts however is a bit stronger cause you use two weapons, double damage. If your defense is a problem, keep your distance with other skills. They are all high damage based so you shouldn't experience problems while using these.
Your passives are the best for high damage, and when using the lighting and poison one, your damage is not comparable to both other classes. This can be pretty well buffed when using high movement speed to make a useful pull of the mobs when fighting in Trials.
Companions? Either again 3 Nogrims so you can focus on high damage, or 1 Maggie with 2 Nogrims. You can aldo try well leveled Eileen's to do the best when using your ulitily skills and make damage to all groups of enemies at once.