My son that just turned 5 last month is obsessed with the Power Rangers also. He wanted that theme for his party and I had no luck finding ideas so I got him to change his mind and we did an awesome lego party.
Tanners birthday was a Power Ranger party. We never had swords or anything. He wore his Power Ranger costume, we had little frisbees with power rangers on them, power rangers tattoos, and a giant 6 ft tall banner. All the kids played with his other normal toys anyway.