Thor is one of the deadliest and most dominant junglers mainly due to his amount of CC, his sheer damage on the double tap as well as the spin. He has never been considered bad, and has consistently been a Top 5 Jungler throughout all metas. His early game is probably his weakest state of game with the removal of Red Pot at level 1, but his mid game and late game make up for this. By levels 12-15, double tap and spin will 100-0 the enemy jungler, mid, and adc. His global ultimate also adds map pressure and makes lanes play more scared. Thor is all in all one of the best junglers across all metas, and will never be considered bad without a serious nerf to his kit.
Thor has many options for his build, and many options for damage that depend mainly on your playstyle, as well as building against the enemy team.
Damage and Core
What else would you build on a pen assassin?
Utility damage item that gives Power, CDR, Mana, and Pen. Great starter damage item.
Flavor damage item. With recent nerfs is replaceable with other damage items, but is still good with Thor's auto attack cancelling. Also helps with mana consumption and regeneration, as well as decent CDR (NO PEN).
Flavor damage item. With full stacks, this item gives the most power out of any phys item in the game (besides Bloodforge, but Bloodforge IS NOT GOOD). Also helps with mana consumption (late game you will never run out of mana)(NO PEN).
Health and Defense
Gives health, CCR, movement speed, attack speed, and offers the passive. Good overall utility item.
Despite the nerfs, this item is still fantastic. Gives CDR, CCR, 40 protections of each, and offers a wonderful passive.
Mantle of Discord
By far the best defense item, but you should only build this if you're ahead.
Finishing the Build
Brawler's Beat Stick
Great damage and pen, also a necessary item if the other team has healers (Get sooner if so).
Almost always the item to finish the build. Not necessary if they aren't tanky, but if they have a normal team comp, always needed.
You get more physical power the more people are around you up to 3 people at 30 power. Also useful to tell if enemies are behind walls.
The Double Tap
Thor throws his hammer, and it comes back to him. Does double damage upon return on enemy gods, does half damage upon return on creeps. You can teleport to the hammer as well.
This ability is Thor's most broken move IMO. If leveled, you will take half of a squish's health at about Level 9. You won't believe how many BS kills I've gotten just stunning someone under tower and taking half their health with this ability. Also, to confuse enemies when you are trying to get away, throw your hammer in one direction, turn and walk towards the enemy, and then teleport to it. For MAX CONFIRMED DAMAGE, level this first.
Pretty standard CC ability. At rank 2, the wall will always confirm the double tap (unless they have CCR). This is why you level the wall to 2 before maxing the spin. IF YOU'RE PLAYING THOR SUPPORT, probably do this, idk.
Standard damage ability. You max this after the Double Tap and then putting the Wall to rank 2. You are also KNOCKUP IMMUNE during the spin, so use this against Bacchus, Awilix, He Bo, etc. FOR MAX CLEAR, level this first.
Anvil of Dawn
Thor's semi-global ult. Many are confused about what the best combo out of the ult is. I was as well, but asked Homeiefe and Adapting their opinions on what to do, and they both said the same thing.
Ult, Auto attack cancel, Double Tap, Auto attack cancel, Wall, Auto attack cancel, spin. This gets you max damage as will wall them off and chain cc them.
-Thor is one of the highest base health assassins
-Great jungle clear
-Great confirmed damage
-Great teamfight initiator
-Lot of skins, Including a T5!
-Never has been considered a bad jungler.
-Thor is easily punishable if his hammer throw is down
-Not the greatest early game
-Still an assassin, still kinda squishy if no defense
-Has bad matchups against Ne Zha and Thanatos.
Like I said above, Thor is never considered a bad jungle pick and never will be until a serious change is made to him. His damage options are great, his mid game fight is fantastic, and his teamfight initiation is some of the best in the game. Thor is necessary to learn if you consider yourself to be a jungle main.