What is the difference between combat role of HAL Rudra and Kamov 226t?

The two helicopters in question belong to two completely different operation platforms.

HAL Rudra, a modified version of HAL Dhruv, is essentially an attack helicopter, but can also be used in unarmed roles like troop-transport, reconnaissance, etc. It’s also known by the name of ALH-WSI(Advanced Light Helicopter-Weapons Systems Integrated). It has Forward Looking Infra-Red(FLIR) and Thermal Imaging Sights Interface, LASER Ranging and Designation, stabilized day-night cameras, Integrated Defensive Aids Suite(IDAS) acquired from SAAB, Electronic Warfare with self-protection, Radar & Missile Detectors, IR Jammers, Chaff and Flare Dispensers, and what not. Its armory includes French Nexter 20 mm turret gun, Belgian 70 mm rockets, 4 x 68 mm or 70 mm Rocket Pods (Air-Force & Army version), Torpedoes, depth-charges, anti-ship missiles(naval version), MBDA Mistral air-to-air missile and air-to-ground missiles, such as the anti-tank Helina missile.

Coming to Kamov Ka-226T(Indian Armed Forces ordered 200 of these), a refinement of the proven Ka-26, it’s a Russian Utility Helicopter. Approval of the acquisition of Ka-226T was given by the Indian Ministry of Defence (MoD) in May 2015 to replace the ageing Chetak (Aerospatiale Alouette III) and Cheetah (Aerospatiale SA-315B) helicopters of the Army Aviation Corps (AAC) and the Indian Air Force (IAF), respectively. The Ka-226T features an interchangeable mission pod, rather than a conventional cabin, allowing the use of various accommodation or equipment configurations. The aircraft is fitted with trademark Kamov coaxial rotors, of advanced composite design, making the Ka-226T highly manoeuvrable and eliminating the need for a tail rotor.

With two HAL/ Turbomeca Shakti Turboshafts, each generating 1000 kW, Rudra is also much more powerful than the Ka-226T, which boasts two Turbomeca Arrius 2G1, each having an output of 435 kW.