Level 1 Taste for Blood is going to be your choice. Any time you kill an enemy with Globe of Annihilation it will increase in damage.

Level 4 you will want to go with Gluttony to give you some heals from your channeled All Shall Burn. This helps a lot in killing heroes.

Level 7 March of Sin gives you the ability to move around faster while channeling All Shall Burn. This makes it so you can move toward fleeing enemies, or away from heroes that try to attack you. It is extremely important as a talent because with TFB once you unload your NUKE then your main damage is down for 10 seconds this means without anything else you are just sitting there doing nothing. If you channel your laser on the enemy you provide a valuable tool for your team. March of Sin gives you the ability to chase or flee much faster.

Level 10 either Black Pool when combo'd with your globe attacks will allow you to stack your TFB in minion waves really fast. Usually, starting off you will have to hit each of the archers and the wizard once or twice with your basic before comboing them. After you get sufficient stacks the combo damage alone is enough to wipe waves.

Level 13 Infused Power will give you more damage on your All Shall Burn which gives you the ability to better focus down targets.

Level 16 Battleborn helps you summon your Summon Demon Warrior whenever your Globe of Annihilation hits enemies. Which should be pretty much all the time. This can do one of two things. One it can save you mana because you only have to cast Globe and less of Demon Warrior... or Two you cast Demon Warrior the same you just have an extra guy popping up which pushes even more.

Level 20 is going to depend on your group comp and situation. I tend to like going Bolt of the Storm for the simple reason that Azmo has no escapes. This really helps you get out of bad situations created because he is the largest hero in the game with no extra move speed talents or teleports until 20. On the other hand Fifth Circle is a huge benefit to some groups because it slows your enemies preventing them from fleeing in many cases. It is especially useful to you if you have someone in group taking an Executioner build.

Just a preface if you looked at the build you notice it is laser heavy. This is makes you extremely vulnerable until Level 7. So be careful since Azmo is an extremely large target and very slow. Even with the movement speed talent you will still be vulnerable to stuns.

Level 1 you will take Master of Destruction reducing All Shall Burn mana cost and increasing its range. This does two things, you can channel your laser for much longer without running out of mana and you can actually out range the turrets on structures.

Level 4 you will want to go with Gluttony to give you some heals from your channeled All Shall Burn. This helps a lot in killing heroes.

Level 7 March of Sin gives you the ability to move around faster while channeling All Shall Burn. This makes it so you can move toward fleeing enemies, or away from heroes that try to attack you. It is extremely important as a talent.

Level 10 Demonic Invasion gives you a minion wave of your own. This can be used in two effective ways to siege structures. One you can send them down a lane (remember they have no timers unlike other spawns) and just forget about them since they will push the lane for you. Alternatively, and more effective if possible, is that you push up to the structures in question and spawn them right there so they dont get killed by enemy minion waves. The second option does however take you away from your group which can cause issues at times so use best judgement.

Level 13 Infused Power will give you more damage on your All Shall Burn which gives you the ability to better focus down targets.

Level 16 Battleborn helps you summon your Summon Demon Warrior whenever your Globe of Annihilation hits enemies. Which should be pretty much all the time. This can do one of two things. One it can save you mana because you only have to cast Globe and less of Demon Warrior... or Two you cast Demon Warrior the same you just have an extra guy popping up which pushes even more.

Level 20 there really is only 1 option in my opinion with the other being situational. Bolt of the Storm is the go to on this build. One for the reason you are going to be sieging and likely they will be trying to kill you frequently so you want to pick it up at 20. Forced Recruitment allows you to double push. If you find yourself needing to actually push two lanes at 20 then that is the talent to take.