Game industry professionals are frequently implementing new methods of addressing ethical issues related to in-game toxicity and disruptive player behaviours associated with online multiplayer games. However, academic work on these behaviours tends to focus on the perspectives of players rather than the industry. To fully understand the ethics of multiplayer games and promote ethical design, we must examine the challenges facing those designing multiplayer games through an ethical lens. To this end, this paper presents a reflexive thematic analysis of 21 in-depth interviews with games industry professionals on their ethical views and experiences in game design and community management. We identify a number of tensions involved in making ethics-related design decisions for divided player communities alongside current game design practices that are concerned with functionality, revenue and entertainment. We then put forward a set of design considerations for integrating ethics into multiplayer game design.