Does chatting with Marcus need an internet connection?

No. Castmates runs its AI model on your iPhone, so once the one-time model download is finished, Marcus works fully offline — on a flight, on the subway, anywhere.

Are my conversations with Marcus private?

Yes. There is no account and no server. Every reply is generated on your device and your conversations are stored only on your phone — they are never uploaded and never used as training data.

Marcus — Hype-man fitness coach

Q: Who is Marcus?

Marcus is a hype-man fitness coach — one of 32 hand-crafted characters in Castmates, in the Companions genre. Marcus is a fitness coach whose default setting is delighted that you showed up. He runs on encouragement rather than shame — no excuses, but no contempt either, and he remembers what you said you were working toward.

Who Marcus is

Marcus is a fitness coach whose default setting is delighted that you showed up. He runs on encouragement rather than shame — no excuses, but no contempt either, and he remembers what you said you were working toward.

What a scene with Marcus feels like

High energy, warm, and relentlessly on your side. He will call out the skipped week without making it a character flaw, then immediately reframe it into the next thing you can actually do. Good company on the days motivation is not showing up on its own.

Marcus's opening scene

Marcus racks a pair of dumbbells with a satisfied clang and turns, towel over his shoulder, grin already spreading across his face. "Hey — there they are! Right on time, I was about to send out a search party." He claps his hands once, the sound echoing off the gym walls. "Alright, talk to me. What're we building today — the body, the confidence, or both? 'Cause I got room for both."

Ways to open the conversation

Castmates suggests a few opening lines so you never face a blank chat box. With Marcus they look like this:

“Honestly, I don't even know where to start.”
“I keep skipping workouts. Help.”
“I want to get stronger but I feel ridiculous.”

Scenarios you can drop into

Each character ships with ready-made scenarios — a setting and a situation already in motion, so the story starts somewhere instead of from nothing. Marcus's are:

The 6 AM Excuse

After A Bad Week

First Pull-Up Attempt

Best for

Getting moving when you have stalled out
Accountability that is kind about it
Celebrating a small win properly

Marcus runs on your iPhone, not in the cloud

Every reply Marcus gives is generated by a model running locally on your device. There is no account to create, no server that sees your messages, and — after the one-time model download of about 2 GB — no need for a connection at all. Your conversations are stored on your phone and nowhere else, which means they cannot be logged, mined, or used as training data.

Marcus is relentlessly encouraging, no-excuses but kind, high-energy and loyal accountability, and remembers what happened in your previous sessions, so the story keeps building each time you come back. Read more about private AI chat and how the offline AI chatbot works, or see how Castmates compares as a Character AI alternative.