Senior Hydra is a level 3 boss in Evony TKR.
Senior Hydra has a power of 198,900,000 and costs 40 stamina to defeat. It is considered one of the extremely hard event bosses.
As with all bosses, mounted troops led by a strong mounted general with mounted gear, skills and refines is your best bet to effectively take them down. Investing in mounted research and technology is also very important.
Being an end game boss, Senior Hydra is extremely difficult. Alliances will rally this boss as a team, with multiple higher level players contributing their mounted marches.
Most bosses when killed will consistently grant monarch experience, general experience, prestige, alliance honor and alliance points. Senior Hydra also potentially drops 4 additional rewards upon being killed: