Kai most recently worked with the National Theatre of Scotland on the lighting design for One Hundred Voices, which opened at the Scottish Parliament in August 2026. Earlier work for the company includes set and lighting for The Beautiful Cosmos of Ivor Cutler, Somersaults, Mancub, Allotment 3 and 4, Little Otik and Home Caithness, as well as lighting for The 306: Dusk, Eve, Puppet Lab - The Tin Forest, Riot of Spring and Pink Mist.

Design credits for other Scottish and international companies include set designs for Plinth (Al Seed Productions) and Tracks of the Winter Bear (Traverse Theatre), as well as set and lighting for The Ballad of Johnny Longstaff (Northern Stage and Harbourfront Center Toronto), A Midsummer Night’s Dream (Lyceum Edinburgh and Vanishing Point), The Beggars Opera (Lyceum Edinburgh, Belgrade Theatre Coventry and Vanishing Point), Inés de Castro, The 8th Door / Duke Bluebeard's Castle (Scottish Opera), Mouthpiece, Enough (Traverse Theatre), Mister Holgado (Unicorn London), The Destroyed Room (Vanishing Point and Battersea Arts Centre), Saturday Night (Vanishing Point, Teatro Nacional São João Porto, Centro Cultural Vila Flor - Teatro Oficina Guimarães, São Luiz Teatro Municipal Lisbon and Tramway Glasgow) and Interiors (Vanishing Point, Napoli Teatro Festival Italia, Mercadante Teatro Stabile di Napoli and Traverse Theatre).

Lighting designs include Lear (Pitlochry Festival Theatre), Scott Silven’s The Lost Things (Sydney Opera House and US tour for Double M Arts & Events), Mistero Buffo (Trolley Problem), Darwin, Nevada (Vanishing Point and Piccolo Teatro di Milano), The Law of Gravity (Scottish Ensemble), Macbeth (Royal Shakespeare Company), Life is a Dream (Lyceum Edinburgh) and Red Ellen (Nottingham Playhouse, Northern Stage Newcastle and Lyceum Edinburgh).

Own projects include Last Dream (On Earth), created with the National Theatre of Scotland and Tron Theatre Glasgow, which was chosen to represent NTS at the Europe Theatre Price in Craiova, Rumania, as well as Entartet, a performance and installation produced with Vanishing Point and CCA Glasgow. For Perth Theatre, Kai also directed and designed Gaslight