Guilty Gear Xrd REV 2 is a standalone expansion for Guilty Gear Xrd -REVELATOR-, a 2D one-on-one fighting game, available on PS3, PS4, Arcade Cabinet, and PC:Steam.
REV 2 features a short list of system changes, two new characters -
Answer and 
Baiken - significant changes to the game's visuals and camera, a complete rebalance of the cast, expanded story content, and new stages. Rev 2 also received Balance Patch 2.1 which introduced further changes to the cast.
Answer is 
Chipp Zanuff's dutiful secretary and is a ninja dressed in a business suit. He can throw business cards and teleport to their location or make shadow clones attack from their location. He can also set scrolls in the air and use various moves when hanging from them.
Baiken returns from the XX series. She is a ronin with one eye, one arm, and a grudge against That Man for creating the Gears that maimed her and killed her family. Baiken has the unique ability to cancel her guard into attacks for free, forcing opponents to attack her in more unconventional ways.
Tier lists are a way of communicating how strong the community thinks characters are relative to the rest of the roster. Lists can be used to understand the current metagame and how strong characters are assuming two players of exactly the same skill level. Tier lists do not decide the strength of the character, and do not decide who can or will win a given match. Opinions vary on exact placement of characters, and only reflect what is currently known about the characters.
Although there will never be a 100% consensus on the exact tier list, the overall relative strengths are generally agreed upon by the majority of the community. Note that Rev 2 is generally agreed to balanced enough that characters considered weaker can still succeed.
character are not ordered within tiers
The tier lists on this page are subjective in nature, and are the products of their individual authors. You can only trust a tier list as much as you trust its author. Tier lists reflect the understanding on relative character strength at the time that they are written. Metas can develop and characters can change after a tier list is made. Tier lists usually do not account for character difficulty, but that can sometimes be a factor depending on the author. Depending on your goals and how competitive you are, tier lists may or may not be entirely irrelevant.
Legacy Tier Lists
Zadi's List
Zadi is a top level Japanese fighting game player with experience in multiple Guilty Gear games. Zadi plays 
Raven.
Source: 4gamer
Zidane's List
Zidane is a high level American Guilty Gear player in multiple games. This transcription assumes the chart is read from right to left. Answer is left out of the author's chart.
Source: Twitter
Teresa's List
Teresa is a long term competitor in multiple Guilty Gear games at a very high level. They are known for their 
Jam.
Source: Twitter
Romolla's List
Romolla is a former top level XRD player turned top level Strive competitor and streamer. She is known for playing 
Sol Badguy.
Source: Twitter
Klaige's List
Klaige is a high level +R competitor and former competitive XRD player.
Source: YouTube
Kizzie Kay's List
Kizzie Kay is a competitive fighting game player who competes or competed in multiple games at a high level, and is partnered with Panda Global. Kizzie Kay plays 
Sin Kiske.
Source: YouTube
faultydefense's List
Faulty is an Xrd player known for playing Answer and being funny on twitter.
Source: Twitter
