Being a winner in the battle-arena in Stronghold2D, not only apexes your victory but also you are rewarded with hard earned coins of your enemies – every time you manage to defeat them. Players then use these coins to purchase “Research” – which can be referred as upgrade points. Once you get some coins, hop to the “Research” option and upgrade the desired skill. Each research skill has a specific assignment and you have to choose what skill you want to research on first. It’s a free choice. It becomes quite enticing how you get functional skills – fresh juice extracted, from earned coins. Each skill is limited to reach up to Level 5 at most. On each skill advancement, the next upgrade cost for that skill will swell up to a new challenge.