In the outlands of Bandle City, there was once a wooded glen where the moon-moths glimmered and the riverbanks overflowed with rainbowfish. In a cottage nestled between the verdant trees lived a yordle enchantress named Norra, with her cat, Yuumi.
Born with magical powers of protection, Yuumi enjoyed a life of leisure for many years, pouncing on sunbeams and napping beneath the mouse-trees. Whenever adventure sparked her interest, she joined Norra on explorations across the material and spirit realms. Norra spent her time collecting strange objects like broken cups, shards of colored glass, and fabric with funny stitching. She examined each artifact with deep reverence, though Yuumi never understood their purpose. Nevertheless, Yuumi would use her magic to protect Norra from harm, and would warm her feet when they returned home.
screw the RIOT writing, its boring af. Basically Yuumi is a yordle who lived in the Bandle city, which is a capital city for Yordles of all kinds (Im looking at you Tristana), with her master called Norra. one day Yuumi's master, Norra, went missing. Yuumi vowed to seek her master out and protect the Book Of Thresholds, aka "Book" (thats how Yuumi calls it). Book of Thresholds gave Yuumi an ability to leap trough portals to other Runeterra's zones. she found a teapot which belonged to her master Norra in one of the Shurima's ruins. and in the end, Yuumi is still searching for her master to this day.
One of the main runes for Yuumi, which is considered the best ones, is:
Primary tree: Sorcery: Summon Aery>Manaflow Band>Transcendence>Scortch/Gathering Storm
Secondary tree: Precision: Presence of Mind>Cut down/Coup de Grace.
offensive>flex>defensive:
+9 Adaptive (5.4 AD or 9 AP)
+9 Adaptive (5.4 AD or 9 AP)
+6 Armor
So where should I start? Oh right explanation on the rune choices
Summon aery is all around rune which gives shields for allies but also attacks enemy champions if you hit them with an ability, aery does not have a recharge time, BUT it has a "comeback" time. Aery counts as a missile which cannot be blocked by anything so it can go trough Yasuo W, Windwall, ability. To be fair, i like to call the "Summon Aery" rune by the name of aery on crack, just because if you manage her travel time correctly you can dish out a lot more DPS with Aery than with Arcane Comet.
Manaflow Band is the best first line choice for Yuumi between Nullifying Orb and Nimbus Cloak (you will not be tanky at any point of time and if mages like Katarina, Akali, Kassadin one shots you even Nullifying orb would not help, and Nimbus cloak for you is literal hot garbage). Band gives you extra mana, same effect like item called Tear of the Goddess, and after you stack the band to max it gives you much needed mana regeneration per 5 seconds. Band's downside however is the extra mana you get from stacking it up because your healing spell "Zoomies" on E takes % of max mana, basically draining all of your mana in 4-5 presses of E.
Transcendence is self explanatory, on levels 5 and 8 you get +5 ability haste, which is in total of +10 AH, and on level 11 Yuumis takedowns (kills and assists) reduce remaining cooldowns of basic abilities by 20% (which means your E could be used a lot more if you have a hypercarry in the team like Nasus, Jax or Sett, who kills champions in 1-2 seconds).
Scortch/Gathering Storm if a rune of self prefference. if you think your games will last more than 20 minutes, you can go for Gathering Storm because scaling wins the games, but if you want early game poke with a lot of damage from level 1 Q.
Secondary tree options is pretty much self explanatory:
Presence of Mind because mana regen is cool, like you were in high school.
Cut down is the most common rune for yuumi players to take because even champions will always have more health than you, and by a big margin. but Coup de Grace is a good rune choice too for chasing enemies who try to run *insert sadistic laugh here*.