A

A is a red letter A. His mouth is located in the "hole" of the letter in both uppercase and lowercase form, with his eyes right between it. His teeth appear long and straight, although they prove to be separate when his mouth is open. He can also use his legs as arms, as shown when he is driving the CAB. A, along with S, Y, and the other letters (except P and G), witnessed how F formed the word "frick" and incited all the Letters to turn against F. Sometime before F attacked A, he grew into an adult.

In A, he introduces himself while making a cool face.

In G, G calls A, B, and C to form the word "CAB" to track down F. A's role in the cab was as the driver.

In H, they drive past F, who is hiding behind H.

In J, "CAB" waits for G as J gets annihilated by I's cannonball shot by F.

In K, "CAB" and G rush toward F beside I, J, and K. F charges I's tittle, planning to annihilate "CAB" and G to kill them for good.

In L, M, N, O, and P, "CAB" and G are mesmerized by The LMNOP Crew's abilities.

In R, A, along with M and P, form the word "MAP" to find F's location. When the letters head for F, A returns to "CAB" to rush towards F.

In T, they arrive, but F uses the period (".") gem to freeze G in place.

In U, "MAP" deforms as the letters prepare their attack on F. However, after F claims M's gem, he sticks M and A together and flings them toward T, who was previously hammered into the ground. Additionally, A witnesses the last moments of C, shutting his eyes right as F shreds C, killing him in the process. B gets his wings bitten off, and F flies away with P. A is devastated and mourns the loss of his friends, B & C.

In V, A realizes G shot P instead of F, shocking him along with all the letters as they mourn P's death.

In W, A appears in N's nightmare as they spell "COWARD." After N wakes up, it appears they have formed "VAN." A was the body of “VAN”.

In X, "VAN" stops as X multiplies.

In Y, they drive to F's cave and deform as V sprints away in fear. Along with G, M, and U, A is swallowed by F's manipulation goo. When F was murdered by Super N's rainbow attack, A, G, M, and U were left in shock due to the outcome, and Q shows why F had gone the path he did.

In Now I Know My ABCs, everyone, including A, feels empathy for F, as they realize he was not evil before Z reversed time to make up for the loss of all the letters. In the new timeline, particularly the Episode 3, A is now in a group with the other vowels: E, I, O, and U. He and E bicker a lot and argue whether the more important letter is the first letter (A) or the most common letter (E).

The vowels all split up to go after the Calculator Ship. A teams up with V, and both go to F's cave to get N's help as well to spell "VAN." When N finally joins, they accidentally run into G and P's baby and tag him along. They continue with chase alongside L, O, and BIKE. However, the letters are almost out of the Numbers' reach, but they witness Z using his ellipses gems to stop them, thus resulting in the Calculator Ship crash-landing. 1, enraged from being unable to escape with X and 2, makes 3 and the letters witness them. A and V along with the other letters watch L and O defeat the numbers, with L using his gem to shake out the Ship's contents (including X) and O conjoining the numbers with his colon gem. L then throws the Ship to F's cave, while A and V watch and N is horrified.

A reappears in Episode 4, where he, V, and N reform VAN and drives to F's cave. N, seen in an emotional crisis, uses his semicolon gem to power up VAN and turn it into "VAÑ", allowing faster travel to F's cave. Upon reaching, N deforms VAÑ and runs to check up on F while A and V watch as debris falls and blocks their path.

In 5, A almost gets crushed by the debris of Z's gems, along with V. BIKE, N, and O pick them up, as well as several other Letters to escape the clones of 5. T leads the group underground as he's now unsure of which path they should take. A is a laid-back and easy-going letter. He has a rivalry with E. Even though he attacked F as a child, he regretted his actions, as shown in Now I Know My ABCs. In the new timeline, he was also worried about F after L tossed the Calculator Ship to his cave.