First, I just realized that Ascendent’s Circle has the Ascendent Set Bonus, but that’s of minor note. (You can’t exactly remove the set bonus affix, which is why that’s a slight issue.)
As far as Eternal vs. Legendary, if you want to add a mythic affix to the chakram (which I recommend doing eventually–Arc is really nice tbqh and I’ve heard that Cosmic Orb is great as well), then you don’t want an eternal because you won’t be able to add sockets.
Okay, so Legendary it is! Thanks so much everyone for all the help. Sorry to ask so many questions.
Arcane is no element at all, right? (I thought it was shock until now)
Does that look right? Was thinking it would still be Legendary. 
Also, I’ve made the Frozen Earth, how do I add Skulldraga to it now? Do I have to make it a wizard item with Jasper, then reroll it, and then Jasper it back to Rogue…??
Yes, that looks right. Arcane is indeed no element. (Adding a mythic makes an item become a mythic item regardless of what it was before.)
As to Skulldraga (and KnightsCharge), you need to use Amber on the weapon and hope that those options appear.
Arcane is an Element, think of it as the Magic Element. monsters don’t have any normal resistance to it (like resistance to Cold Element on Ice Maps, which gives monsters 25% less damage from Ice attacks), but can have Greater Resistance to it. I am not sure, but I think monsters can also become Immune to Arcane. for Builds that use Prismatic (Wizard Talent or using the Ascendent Set), if you have Arcane as your Base Element on your weapon, and you have Ascendent (5), that is a 62.5% chance for getting one of the other 4 Elements instead. if you have one of the other 4 Elements as the base Element for your weapon, then it is a 62.5% chance to get the other 3 Elements, but not Arcane. in the Set description for Ascendent, it says you need the Arcane Element to get the Weaken part of the Set to work. I don’t know if that is still true after Patch 3.0, but if it is, and you don’t have Arcane Element, then you need to put Weaken on your Weapon, especially if you are using the Arcanist Set with Ascendent.
@Sequince and that Arc Chakram, if it was still Legend when you turned it into a Mythic Item, it is still Legend, think of it as a Mythic Legend item.
Edit: just found this post.
Where would you recommend putting Stat Distribution and Hero Points beyond the ones you listed in the guide?
I made the build and it’s quite fun so far! 
Thanks for this.
Anscendent bonus is good if you use an elemental attack
I put stat points all in power.
For hero points, you probably should just put them all in the bottom 4 skills.
The four bottom skills is a must.
And before you ask why fortune ? You will find better stuff. The rest is about staying alive. You can add damage to your weapons
Fair enough, I’m only missing the +2 to all sets (Elixir) and Twister proc on the trap now.
I’ve tried a few times on rolling Twister, this last one I got Torrent. Should I keep trying for twister? Torrent seems to summon 3 little tornados… kind of the same thing right? /hopes
they are different, you should get an item with Twister Proc and see how they are different so you know which is best for your build. if you are using a Rogue, you can go either way, depending on the build, since Twister is a Wizard Skill and Torrent is Warrior, so the only way to really make them do more damage is 2x +5 All Skills and/or +10 Epic Twister/Torrent on your Pet. also, take a look at the Skill description on the item that they are usually on, and if you can, take a look at what gets boosted when you put Hero Points into the Skill. you know, like Hit Frequency, increased Area of Effect, stuff like that. I think the biggest difference is Twister has Taunt and Torrent doesn’t.
I have used Twister for a long time, and really like it. I haven’t used Torrent much, but have dodged a lot of them in the Arena. that is why I said try out both to see which goes well with the build you have in mind. I currently use Storm more than Twister, but I had a Hireling Build that was using Twister with Teleport, and it was pretty good for a silly Ascending Hireling Build.
I use storm too. Twister is good if you want to be a sitting duck 
watching my Hireling use Twister made me wish I was an A.I. 
Hirelings are so much better at killing lol 
How do you get a hireling to use Twister?
You can either:
Have your hireling be a wizard and use gauntlets
Change the special of your hireling’s MH to twister
Get a.m. item with twister proc on your hireling