For 2023, the New Year Servant in the Japanese server of Fate/Grand Order is Grigori Rasputin. Rasputin was a historical figure from 1910s Russia. However, in Fate/Grand Order, he takes on the form of legacy character Kirei Kotomine. He is an SSR Alter Ego, and is a limited-time Servant. This means that if you do not pull him while he is on the banner, you will lose your chance to do so until his re-run.
Jouji Nakata (Guilty Gear, Persona 5) will reprise his role as Grigori Rasputin in Fate/Grand Order. His kit prioritizes supporting and buffing himself. He can also remove buffs and heal an ally with his first skill. His Noble Phantasm, Zazhiganiye Angra Mainyu: Overflowing Heart of Darkness, is an Arts attack that deals damage to all enemies. It will also inflict Burn and Curse upon them. Finally, it has a chance to Insta-Kill Good enemies.
— 【公式】Fate/Grand Order (@fgoproject) December 31, 2022
As well, the GSSR campaign is ongoing in Fate/Grand Order. You will have to use your paid Saint Quartz in order to pull from it. But you will definitely get an SSR. This year, you will also get a free Holy Grail if you pull from a GSSR. You can only choose one GSSR banner, no matter how many paid Saint Quartz you have. For 2023, the GSSR banners are split based on their class and what type of Noble Phantasm they have. For instance, Miyamoto Musashi is on the Saber (Single-Target NP) banner whereas Charlemagne is on the Saber (All Enemies NP) banner.
Fate/Grand Order is readily available on mobile devices. The GSSR and Rasputin banners in Fate/Grand Order are on the Japanese server only, and will run until January 11, 2023.