Problems in
Writing fights?
-- Your first and most major problem is how to
Write that kind of battle scene without confusing the Readers.
-- Your next problem will be making sure that your summoner character doesn't look like a
Mary Sue/Marty Stu, over-powered, Wish-Fulfillment character.
--
Common Mary Sue Traits -- TV Tropes
Also, have you built a magic/spiritual tradition that
Allows for summoning?
What kind of research have you done in Magic and Mythology to create the religious/spiritual background for your brand of magic? This is needed to make any form of magic not only logically operable, but feel Real to the readers.
What magic or spiritual tradition are you basing your magic on?
In JJK, the author bases their summoning powers on the traditional Onmyoji skill set. In fact, most of the 'powers' in JJK are from traditional Onmyoji myths and stories. So are many of the monsters.
The movie
Black Panther uses African traditions for their magic.
The Harry Potter magic system was pretty much made up by the author, but was influenced on Celtic and Norse traditions.
My magic is based on the Wiccan traditions and borrows heavily from the Celtic fairy stories and myths from the British Isles.
On the flip side, Author Jim Butcher's Modern Wizard series; the
Harry Dresden books, uses a magic system based on the Dungeons and Dragons role-playing game. He freely admitted this.
In fact, many,
many anime, manga and manhua use the Dungeons and Dragons magic system, a game created in the early 1980's, and based on JRR Tolkien's books.
And it's Obvious to all of us that actually play D&D.
Some signs that the Author is using D&D books for their magic:
-- The power Blink. This is an exclusive D&D ability. It does not exist historically.
-- A wizard's abilities are magically bestowed by Books.
-- A healer's power is Green.
-- The goblins are Green.
-- The Orcs look like Pigs and are Green. This whole race comes straight from JRR Tolkien, which the D&D game was based on, however Tolkien's Orcs were not Green. The color change was introduced by the D&D game.
-- Rings of power.
-- Dungeons.
Next, you need a Reason, or Excuse, for magic to exist in your world.
And this is just the Beginning.