Do you know any effective way to summon a hero 5*? A theory, for example …
Yes. Build and run as many TC20’s as you can. Run them full time (I run 2). This is the most effective and least expensive way to get 5* heros. I currently have 18 5* heros. 16 of them came from TC20. 1 (actually my 1st, Richard) came on a 300-gem pull. The other, Elena #3, came from a free pull of 100 Atlantis coins. I have 3 red 5* heros, every one an Elena…
Spend LOTS and LOTS of money is the most sure fired way of all.
Aside from running your training camps at level 20, as @Ragnarock advised, your best bet spending money is to save for Atlantis pulls. You get the most bang for your buck, with the added benefit of getting ascension mats every 10th pull.
If you don’t have Falcon and Jackal, it might be worth pulling a little during the Guardians event, but otherwise I’d avoid the events, as the odds of getting anything worthwhile aren’t that great, and you don’t get the mats you get from Atlantis.
Save your epic hero tokens for use during the seasonal events—the best one being the Winter event in December.
Try logging out the game within the first 5 minutes or last 5 minutes when the event or atlantis gates open or close. Log in again but immediately close the game. Once you open again the game, the first business should be to summon from the special portals. It will give you crap. Trust me. It works.
Here, simplified that for you.