If you went to Hateno Village and heard that there's a guy called Robbie giving you upgrades for ancient parts, you should go there, it's on the top right corner of the map in the Akkala Region.
If you have gone there already, you've seen the Guardian armor. Yes it's super expensive, but it's definitely worth it in the long run. Ancient Cores can be a pain, but if you mark the particular towers on your map where there are walking guardians, and granted you know the trick to Shield Parrying (parry a split second AFTER you see the guardian's eye light up), you can farm them for ancient cores, then it gets pretty easy.
For Rupees you should unlock the top left region which is full of snow, and just beside the tower when you jump off from running straight when you teleport there, under the tower you can see a small house. There's a guy there with a snowball minigame, and if you get the hang of this (throw, not drop the snowball, at the area where the snow is leveled and there are no hills, between the rock and the tree after walking a bit near the cliff where the snow goes down), you can get 300 RUPEEES PER MINUTE! This is the most effective way of rupee farming in the game.
Now on to the trick. You know those Major Test of Strength Shrines right? I believe there are about 5. Find all the shrines first. I'll post screenshots later on their location. You may have heard by now that Blood Moons respawn the guardians in these shrines too, so make use of this.
First get the full armor set from Robbie's Robot.
Upgrade fully or to a minimum of two upgrades per armor at Great Fairy Fountains. (find the minor test of strength shrines to easily farm for parts)
Equip a guardian weapon while you're wearing the full armor set, you will get bonus damage for the armor (around 80% more damage), PLUS you will get more damage for using the guardian weapon against the guardian. This means you can beat them pretty quickly and easily.
3.5 (Optional). Use a frost weapon to stun the guardian, now all your damage will be tripled while the guardian is frozen, and you can avoid it's crazy attack modes. <Thanks to u/rayzorium> You can also hold Y using a two handed weapon (Guardian Sword++/Axe) and keep hitting the guardian, works pretty well.
Kill every guardian in these Major Test of Strength shrines and collect their weapons and loot each time.
Rinse and repeat and you will always have high quality weapons in the game plus guardian loot! The best part is these guardians drop 3 very strong guardian weapons per each guardian (Sword ++, Axe +++, Spear ++), and armor cores/giant armor cores from time to time!
You're now OP. (no I am)
I've been doing this for a while and it's really fun to defeat these guardians once you get the hang of it. It's always best to equip your lowest damage guardian weapon, the spear is the best for this, and do a flurry rush each time a guardian attacks to give the most damage and avoid breaking the other weapons.
-When the guardian uses his sword, just after you see his sword shake and stop shaking, you jump to the left/right immediately to initiate slow motion.
-For the axe, wait till the guardian moves the axe two times, and leave almost a second after that and jump backwards to initiate slow motion.
-For the spear, jump to the left/right after the guardian shakes the spear, like the sword.
You can also get a flurry rush when the guardian is doing his spinning attack, you just have to dodge back just when his "fan" nearly touches you. Just make sure you don't dodge too late, cause dodging too late is actually the real problem compared to dodging too early, if the guardian is near you, dodging early enough almost always triggers a flurry rush scene relative to dodging late where the chances are low.
When the guardian does his laser thing in circular motion, run away, and then glide using the paraglider and shoot his eye at the right time, then press X thereafter and go right above it and do it jump attack (Y).
In his last moments he'll do the laser beam, but this is different from regular laser beams. You have to parry immediately when all the blue light has absorbed into the guardians light, immediately when all the light goes to the center, not even a split second after. The difference with other guardians is that you parry a split second after you see their eyes glow, but in this when the light is in its center, it's when you parry immediately with full reflex action!
Hope this helped anyone having trouble with guardians or weapons. 🙂 | | | EDIT: The Shrines as promised, screenshots coming soon. Not sure if this is all, but this is what I found so far:
-Tena Ko'sah Shrine: Below Tabantha Tower on the map, and just under the end of the road.
-Mozo Shenno Shrine: Above Rito Village on the map, north-east of the river that looks like a deformed carrot.
-Goma Asaagh Shrine: East of Mozo Shenno Shrine, just below the "tains" in the Hebra Mountains name.
-Kema Kosassa: A bit above the word "Risoka" in the word Risoka Snowfield in Gerudo Highlands.