📚 Knowledge
• Basic knowledge — from Oracle level 1
• Knowledge, tier 1 — from Oracle level 31
• Knowledge, tier 2 — from Oracle level 36
• Knowledge, tier 3 — from Oracle level 41
How to use. Four branches, each unlocked by Oracle level: basic from 1, tier 1 from 31, tier 2 from 36, tier 3 from 41.
Tier 3 already has the cost of Secret Knowledge III and of unlocking Tier 9 troops. The other branches are still being collected.