Gorgon

She has the highest attack stat of any 4*, a 50% attack buff for her NP and a 50% crit buff for 3 turns, as her main selling points charging the whole parties NP gauge on a buster NP is really nice too. Her NP can hit very hard thanks to that 50% damage steroid even out damaging many 5*s and being resisted by basically nothing with only one Moon Cancer existing for the foreseeable future. Her overall NP gain is pretty solid too with 3.8% guaranteed every turn and the 15% refund.

Her only real flaw is the avenger class's innate lack of star weight which forces you to either have lots of stars or use a CE to correct it. Basically I'd say she's a mini Jalter both being buster-crit servants with the highest attack making use of a 1 turn 50% buff and 50% crit buff to fuel their damage engine Gorgon just trades some damage for more survivability and lacks a star draw skill of her own.