I am a second year PhD student in the CS Theory group of AUEB, advised by Vangelis Markakis. Previously I received a MSc in Machine Learning and Data Science and a MEng in Electrical and Computer Engineering from NTUA, working with Dimitris Fotakis. My research spans three main axes: 1) Fair Division where I have mainly worked on EFX allocations for goods/chores (one published paper, one under submission in a major AI venue), 2) Optimisation and Games where I am focused on learning algorithms beyond zero sum games (one manuscript) and 3) Mechanism Design with Predictions. My research is supported by an Archimedes AI PhD Fellowship. Personal webpage: https://santorinaios.github.io/