Short answer / recommendation
- If you need a programmatic, fast, reproducible bulk pipeline (hundreds+ images) with reliable seed control: lean to Leonardo AI. It offers an API/credit model and batch tools that make automation straightforward.
- If you prioritize a very distinctive, highly stylized “premium” look and don’t mind Discord-based automation manual steps: Midjourney can give better painterly flair but is fiddlier to scale consistently.

Decision criteria (choose by what matters most)
- Automation & scale: Leonardo (API, batch endpoints) > Midjourney (Discord bot or workarounds).
- Seed determinism & reproducibility: Leonardo generally easier to lock programmatically; Midjourney has --seed but can still show variation across runs.
- Output aesthetic: Midjourney often yields more dramatic, painterly styles; Leonardo tends to be faster-to-iterate and more neutral/controllable.
- Cost sensitivity: depends on your plan/credit purchase; Leonardo’s credit model often wins for high-volume use, Midjourney can be OK if you have a high-tier plan. Measure cost-per-image by running a 100-image pilot and dividing credits/cost.
- Team skill / infra: if you have devs to script Discord interactions, Midjourney is viable. If you want an API-first route, use Leonardo.

Practical checklist to run bulk character generation
1) Define anchor assets: a reference pose or base silhouette (PNG) for consistent proportions. Use it in img2img or as reference.
2) Create a prompt template (placeholders for variables):
- Example: "{character_name}, 3/4 portrait, neutral background, studio lighting, clean linework, high detail, camera 50mm, flat color palette, seed:{seed} --ar 2:3"
3) Prepare a CSV with columns: id, character_name, costume_tokens, color_palette, seed. Generate a deterministic seed list (e.g., 100–99999 range) and store it.
4) Test small: run 20 variants first to check drift and prompt stability. Lock parameters (aspect ratio, focal length, style weight) once satisfied.
5) Batch size & rate limit: do 20–50 images per batch, check quality, then scale. If using Leonardo API, parallelize to match your credits and rate limits. If using Midjourney, use queued/relax modes and automate via Discord carefully.
6) Post-process step: run a light pass for cleanup (background flatten, color normalization, or face alignment) to ensure consistency across variants.

Prompt tips (consistency-focused)
- Use explicit camera/pose tokens ("3/4 portrait", "full body, facing left").
- Anchor style with short tokens: "studio-photo, clean-lined, cel-shaded" rather than free-flow adjectives.
- Use negative prompts to remove artifacts: "no text, no extra fingers, no watermark".
- Keep most of the prompt constant; only swap the variable tokens (name, outfit, color).

Best-for / Avoid-if
- Best-for Leonardo: teams needing API, deterministic pipelines, lower per-image bulk costs, fast iteration.
- Avoid Leonardo if you require the distinct painterly signature Midjourney produces.
- Best-for Midjourney: small teams wanting standout artistic variants and willing to spend extra time on automation.
- Avoid Midjourney if you need strict reproducibility and API-first scaling.

Final practical note on cost-per-image
- Exact costs change frequently. Run a 100-image pilot on each service and compute cost-per-image (credits or subscription / images produced). Use that number to forecast your budget for the full run.

If you want, I can: 1) draft a CSV/prompt template for your specific character fields, or 2) outline a sample Leonardo API batching script. Which would help more?

Compare Leonardo AI and Midjourney