Calasin

"Sell to your heart's content until we clear our warehouse."

- Calasin, Volume 2 Annex

Calasin (also translated as "Charasin" and "Karashin"), also known as Young Boss Calasin, is the guild master of Shopping District 8, one of the top three production guilds in Akiba. He is a Human Summoner-Merchant and a member of the Round Table Alliance. His Overskill is Multi-Line.

Calasin's real name is Yousuke Mikami (三上洋介 Mikami Yōsuke), and he works in an advertising agency.

Personality
Calasin is considered to be a very shrewd businessman and will take advantage of any transaction or deal to ensure that he gets the largest profit possible.

Before the Catastrophe
Calasin worked in an advertising agency. In Elder Tale, he partied with Marielle occasionally until they formed their own guilds and were too busy to interact with each other as a result.

The Catastrophe arc
Calasin can be seen in the Inn, discussing something with another player.

Round Table Alliance arc
Calasin checks on the guild's inventory with Taro, noting that they were almost empty. Having been summoned by Marielle and Henrietta for a meeting, he decides to take advantage of the situation. However, having been given instructions by Shiroe, the two women manage to persuade Calasin into agreeing to supplying them with ingredients for the Crescent Moon Refreshment Stand for 30,000 gold.

He stays to attend Crescent Moon's meeting with The Roderick Firm's and Marine Organization's guild masters Roderick and Michitaka. Along with the other two guild masters, he comes under the false conclusion that there was some sort of new legendary quest that Crescent Moon Alliance was undertaking and agreed to cooperate with Marine Organization and The Roderick Firm in donating a combined total of 4.5 million gold to fund this quest. Later on, the truth about the gold's use is discovered, but the three crafting guild masters receive Crescent Moon Alliance's food recipe secrets.

Calasin and the bosses of the other Production Guilds reveal that they had created a Steam Engine, which proves that out-of-game devices can be created. As a result, new inventions and products will be in high demand, and therefore will get the economy going. As a result, he and the other bosses agree to the creation of the Round Table Alliance.

The Conference of the Lords arc
Calasin and Roderick stay behind to work on the Ocypete and other projects, after beating Michitaka in a game of rock-paper-scissors.

The Return of the Goblin King arc
Shiroe and Akatsuki lead Raynesia to Calasin in order to prepare her new outfit for the speech to assemble a expeditionary army against the Goblins' hordes.

Calasin goes the headquarters of the Round Table Alliance Expeditionary Force established at the Midraunt Equestrian Park, where he leads the Telepathic Communication network, that enables the constant flow of information throughout the army.

Fallen Guardian arc
Calasin had accompanied the mission to Seventh Fall as part of the rearguard/support, but this mission was terminated after Krusty's disappearance.

Route 43 arc
Calasin wanted Minori to transfer to his guild, for which he gets called a lolicon by Isaac.

Noosphere arc
Calasin has opened a branch of Shopping Street 8 in Maihama and regularly chats with (or annoys) Isaac, who has also been stationed there. He provides Isaac with updates from the Round Table, such as the heightened tensions between Minami/Westelande and Eastal and about the arrival of the Genius monsters.

Calasin provides Isaac with an earring that detects ambushes, which is critical for saving Iselus' life the night of his birthday, when People of the Earth assassins from Minami arrive to slay the boy.

Log Horizon: New Adventure Land
Calasin is a Super Rare recruitable character in the Log Horizon SNG. His special summon is an Undine.

Trivia

 * In Mamare's original character drafts, Calasin was a Swashbuckler instead of a Summoner.